As of January 31, we have documented 57 people caught in 42 separate avalanche events. Seven of the people have been critically (head under the snow) or fully buried, and two have died. 60% of the involvements this season occurred in January alone, including both fatalities.

Those are impressive and scary numbers.

Backcountry tourers triggered and were caught in this avalanche while ascending, Sawatch Range December 14.

How does this season compare to previous years? Before answering that question, there are several things to consider when we talk about avalanche accidents. We do know how many people avalanches kill. Fatal accidents are investigated and documented, which gives us confidence in the data. We do not know how many people are caught, injured, or buried in avalanches. We only know what people tell us. Many involvements go unreported, for reasons varying from embarrassment to people not knowing that we are collecting information or even that the CAIC exists. When there are well-publicized incidents, we tend to learn about other events. Thus, the number of people caught is an approximation, but we think it is indicative of patterns in avalanche involvements. The number of fatalities and incidents is relatively small, too. That means a single large event, like the 2013 accident in Sheep Creek, has a large impact on annual and multi-year trends.

So, caveats in mind, how does it look like 2018-19 will compare to previous years?

Comparing fatalities, 2018-19 looks similar to recent years. In four of the previous six winters, there were two or three fatalities by the end of January. The differences in total seasonal fatalities over recent winters tend to appear in February or April. Over the last few decades, most fatal avalanches occur in January, February, or March. Accidents in the spring separate typically tragic from exceptionally tragic seasons.

Comparing involvements paints a different picture. There were 32 people caught in avalanches in January 2019. That is nearly three times more people than in previous Januaries. Of the past 40 months with avalanche incidents, we only recorded more involvements in February 2013. The 56 cumulative involvements this year are far more than we recorded for all of 2017-18, 2015-16, and 2014-15. If we project similar rates to the end of the season, 2018-19 will be by far the most people involved in avalanche that we have recorded.

Only 6% of the people caught in avalanches in January died. That is slightly better than the long-term annual fatality rate of 8%. Several months, like February 2016 or April 2013, we documented relatively few involvements compared to fatalities and the fatality rate was over 20%. Those months highlight the potential uncertainty within monthly comparisons and the sensitivity of the small numbers in the dataset.

While these comparisons are interesting, there is not a single, easy explanation. There were 1113 avalanches record in January 2019, making it among the highest monthly totals. More avalanches were recorded in January 2017, though, with no fatalities that month. It is not simply a function of more avalanches. The type of avalanche may contribute. This winter, many of the avalanches ran on persistent weak layers while many in January 2017 ran on storm instabilities. More people are recreating in the backcountry, which could increase the number of interactions with avalanches. Those people may be reporting their involvements more often than in the past. We are learning about more close calls and successful companion rescues, possibly improved avalanche safety equipment. The line between avalanche tragedies and close calls may only be a matter of luck. A few events go slightly different–someone misses a tree, someone is caught further out on the slab–and our season could look very different.

We’d like to extend a Happy New Year greeting to all the Colorado backcountry enthusiasts. It’s been a great start to the snow year. The map below shows that a good portion of the state has near or well above average snow-water equivalent as we close out 2018. The Southern Mountains are still playing catch up, but a New Year’s storm is in the process of delivering some ample snowfall to the area. These are great conditions for winter recreation, but we are in the middle of the avalanche season and we want everyone to both have fun and stay safe.

Snow-water equivalents on December 31.

Avalanche danger is ramping up with the New Year’s storm, and avalanche watches and warnings are in place for the San Juan Mountains. Although we likely won’t see enough snow for warnings in the Sangre de Cristo Mountains nor the Central Mountains, there will be enough of a new load to create dangerous avalanche conditions. Conditions are relatively safer in the Northern Mountains, but we still have stiff layers of snow resting on buried weak layers. You can still trigger a dangerous avalanche on steep wind-loaded slopes.

It’s not unusual for us to see avalanche accidents around the holidays and New Year. Over the last 10 seasons, we documented 11 incidents and accidents during the first week of the New Year. Three of these were fatal accidents. We don’t want 2019 to start out on a tragic note. Don’t let the excitement of new snow lead you into terrain not suitable for the changing conditions. Read the forecast, and pay attention to the travel advice. We want everyone to enjoy the great riding conditions and return home safely to friends and family.

In April the CAIC shifts from winter to spring operations. The exact date changes each year based on conditions. We make this change as the avalanche conditions become more uniform across the state and as the number of observations we receive decreases, making it difficult to assign danger ratings with confidence. Avalanche season doesn’t end in April, so instead of issuing forecasts for each backcountry zone we issue a single discussion of avalanche conditions for the whole state. As we approach this transition, here is what you can expect for the rest of the spring, summer, and fall.

We’ll continue to issue weather forecasts twice each day through the end of April. We typically issue a Statewide Avalanche forecast on Sunday, Wednesday, and Friday by 3pm. This year because of support from Cripple Creek Backcountry, The North Face, Bristlecone Mountain Sports, Ragged Mountain Sports, and Ute Mountaineer, we will be issuing zone forecasts for an additional week and then issuing the Statewide Avalanche forecast everyday through the end of April. In May we will issue the statewide forecast three times a week through Memorial Day. Our goal is to provide up-to-date and accurate avalanche information, so if conditions change we will update this product on any day it is warranted. We will also continue to issue Avalanche Watches, Avalanche Warnings, and Special Avalanche Statements any time the avalanche danger spikes or requires special attention. You can expect this through the summer and into the fall when we begin issuing regular products again on November 1.

by Nick Barlow

Colorado’s snowpack received much-needed help during January and February, including the first significant winter storms in the Southern Mountains. As we eye our next period of active weather ahead, we have an opportunity to place this year’s snowpack into its historical context.

Below, you’ll find recent data from the NRCS SNOTEL network. Data from these automated mountain weather stations shed light on the current condition of our snowpack. It’s been a difficult winter so far for snow lovers, but how bad is it really?

Winter storms since January 1st increased the statewide snow water equivalent (SWE) by about 19 percent vs. the historical median. The Southern Mountains realized the greatest gains during this period. The Wolf Creek Pass SNOTEL station measured 13.3 inches SWE since January 1st, which is 146% of the historical median for this period. However, the statewide seasonal numbers remain disappointing. The map above displays a general north-to-south gradient in snowpack deficit, with most stations in the Southern Mountains reporting less than 60 percent median SWE to date. Deficits are less in the Northern Mountains, where a few sites have SWE numbers near or even above the historical median. SNOTEL data in the Central Mountains varies significantly, with generally-better numbers observed east of Aspen and Crested Butte.

The chart above ranks this year’s SWE to date vs. all past years on record. The number indicates how many years had less accumulated SWE on the same date, so 1 indicates the driest year on record. The dataset is not standardized, as the period of record varies by station. Despite frequent winter storms since January 1st, some SNOTEL sites remain at their lowest SWE levels to date on record. Current ranks are generally better at selected sites in the Front Range, Vail & Summit County, and Sawatch zones. Notably, the current water year ranks seventh wettest at both the Buffalo Park (south of Rabbit Ears Pass) and Deadman Hill (west of Red Feather Lakes) SNOTEL stations. Hard to believe?

These products display snow water equivalent on the ground as of February 25th, but how does observed precipitation since November compare historically?

Accumulated snowfall since November 1st is at or above the 30-year average in portions of the Park Range, Northern Front Range, Sawatch, and San Juan mountains. Significant snowfall deficits exist west of Vail Pass, extending throughout the Aspen and Gunnison zones. Local variability certainly exists beyond the resolution of this product. Regardless, these numbers may appear surprising, unless we consider this winter’s pattern of storm frequency.

The current water year (October 1, 2017 – September 30, 2018) began with above-average mountain snowfall in portions of Colorado. Appreciable winter storms arrived during the beginning and middle portions of November, and also during the end of December and early January. Most recently, measured snowfall in February 2018 is above average for much of Colorado. The result is above-average snowfall this winter for some areas, but storms were too few and far between for the snowpack to develop accordingly. In other words, the storm snow sat idly for weeks at a time, while precious SWE sublimated or melted away. The redistribution of snow on the ground via frequent wind events could have also played a role.

On average, the statewide SNOTEL network realizes peak SWE numbers by April 9th. This means we have around one and half months remaining to make up ground on the historical numbers. Can we recover from the historically-dry fall and early winter period?

The chart above displays non-exceedance projections for our current water year. The heavy red line shows the observed statewide SWE as of February 24th, 2018. The thin colored lines (blue through red) indicate the range of possible futures. Blue-tinted lines indicate generally wetter scenarios, while red-tinted lines indicate drier scenarios. Here you can see the minimum, maximum, 10, 30, 50, 70, 90 percent non-exceedance scenarios. For example, the 90 percent exceedance line represents the boundary in the historical record in which 90 percent of the time any day’s SWE value will be below this value.

Only under the maximum and 90 percent statistical scenarios do we approach or exceed average statewide SWE before the spring runoff. While not impossible, both scenarios have a low probability of occurrence. The green line is the most-likely statistical outcome based on historical SNOTEL data. There is a 50 percent chance we end up either above or below any point on the green line. You can see we only have an outside chance of our snowpack recovering to long-term median values.

This chart breaks down peak seasonal SWE by month, displaying the current water year, past three water years, and 30-year median. With February nearly finished, Colorado’s snowpack is about 57 percent of the median peak. With our snowiest months already in the bank, median SWE in the mountains come April is an increasingly-unlikely scenario. Unlikely, but not impossible. Every water year has its own unique pattern, and yearly data rarely follows the historical curve. Intra-seasonal variability is common in Colorado, as our snowfall can arrive at different periods of the water year.

Unfortunately, low snowpack levels have consequences well beyond winter recreation. State commerce and tourism can suffer significantly during and directly following a dry winter. We also depend on a healthy snowpack for water supply and agriculture during the drier months. Finally, wildland fire danger can increase significantly following dry winters.

We all want more powder to play in, but there is much more at stake in the crucial weeks ahead. Winter snowfall is the lifeblood for continental climates like ours.

By Brian Lazar and Blase Reardon

Fall snow in the mountains – white snow bannered between blue sky and golden aspens. What to make of it? Maybe you hear people bemoaning it as a sign that their biking, climbing, fishing or gardening seasons are coming to an end. Maybe you hear others extolling it as the promise of a powder-filled winter ahead. Maybe you hear grizzled veterans grumbling that it’s too early, and we’re on the road to developing our first unpredictable and potentially dangerous weak layer. Let’s consider that last response, and outline some tips on how to deal with that issue.

The fall snow is shallow. That’s its most significant feature. It’s susceptible to melting or weakening, and both processes can have long-term effects on snowpack development and avalanche conditions as the winter progresses. The outcomes depend on future weather.

Melting:
A combination of radiation and heat can melt the early season snow. Sunny slopes are the first to melt off. If temperatures are warm enough, even shady slopes can melt back to bare ground. A prolonged spell of sunny, warm weather will leave slopes (especially those receiving direct sun) bare of snow, or dotted with thin, discontinuous snow patches. This would a good thing from an avalanche perspective. It would mean subsequent snowfall will be falling on mostly bare ground, without preserving any weak layers at the bottom of the snowpack.

Weakening:
High-elevation shaded slopes aren’t as impacted by radiation and often don’t warm enough to melt snow. On these slopes the thin snow cover lingers. Temperature gradients – in this case the difference in temperature between the ground and the snow surface – can be very high. The temperature near the ground hovers near freezing. At the snow surface, it’s generally colder; sometimes much colder. High temperature gradients promote faceting of the snow grains. With time, this thin layer of early season snow can change into a weak layer of large-grained facets; a layer that collapses when sufficiently loaded. That weak layer will be at the base of any snowpack that accumulates above it. That’s a bad thing.

Some of both:
If the radiation and heat aren’t sustained, they might leave just a crust on the surface of a shallow snowpack. Crusts near the base of the snowpack are notorious for producing thin layers of facets that can persist for long periods. That means ongoing Persistent Slab avalanche problems, if they’re buried. Some of our worst years for Deep Persistent Slab avalanches occurred when early season snow first faceted, and then melted just enough to cap the basal facets (depth hoar) with a thin crust. Neither of these scenarios is great for our avalanche future.

So, what’s a snow-lover to do at this point? Monitor the weather and snowpack from here on out. Below are some things to watch:

• Snowline elevation: Put a number on the lowest elevation at which you see snow. Find some markers on a slope you can view regularly, compare them to a topographic map, and check the snowline against those markers. Once snow starts accumulating, you’ll know the elevation above which you need to factor basal facets into your assessments. Or conversely, the elevation below which you don’t.
• Aspects: Be very conscious of the aspect the slopes where you do and don’t see snow. Use an online mapping tool or a compass to verify your impressions. Being able to differentiate slopes by aspect will again help you include basal facets in your assessments when they’re likely to be present. And deemphasize them when they’re not.
• Snow surface: You’ll need firsthand info to determine whether a crust/ facet combination is developing. That can be opportunistic – checking for it if you are up high or asking people who have been – or planned.

Images of your favorite backcountry areas can serve as great references later. The most useful images are those taken just before the season’s snow accumulates, when you can see the distribution of any persistent old snow. Because it’s hard to time that, take images whenever good weather allows.

These practices are focused on determining the distribution of potential weak layers. They don’t tell us much about the actual layers. That we can learn once winter hits in earnest. For now, think “where.”

At this point, we’re hoping for one of a couple scenarios:

1. The snow on the ground now melts away back to bare ground. That way we could start from scratch when we’re more likely to get consistent snowfall.
2. Bury this early season snow with more snow; lots of it and fast! Once we have snow on the ground that is likely to stick around, the more quickly and deeper we can accumulate more snow, the better in the long run. We’re hoping for a snowpack deep enough that temperature gradients aren’t high enough to promote faceting/weakening of the snow on the ground.

Many places that picked up more than 1 or 2 feet of snow in early October now have enough snow to make scenario 1 unlikely. Scenario 2 doesn’t look great either with the mid-range forecasts. That’s leaves up hoping we don’t cap our currently faceting snowpack with a crust. It’s not the best way to start, but it’s not the worst (yet).

by Brian Lazar and Ethan Greene

Santa delivered a lot of snow to Colorado in the past two weeks, just in time for Christmas. Have we been naughty or nice? Well riding conditions have been fabulous, but there have been some impressive avalanches.

The last storm brought significant snowfall and avalanche activity, but since then the snowpack has been getting stronger and we’ve seen fewer avalanches and less cracking and collapsing.  Paradoxically, this does not mean things are necessarily safer for the backcountry traveler. The likelihood of triggering an avalanche is decreasing, but the size and consequences of avalanches that do release are steadily increasing.  This trend has prompted discussions amongst our forecasters about whether or not we are moving into a new risk paradigm, and perhaps, a new avalanche problem: Deep Persistent Slab (DPS) avalanches.

DPS avalanches have many characteristics in common with Persistent Slab (PS) avalanches. Both break on persistent weak layers. You can trigger both remotely and from low-angle slopes. Both of these types of avalanches can fail in surprising ways, breaking across and around terrain features that would contain a Storm or Wind Slab avalanche. PS and DPS avalanches have a lot in common, but there are some very important differences that affect how we avoid them and manage our own personal risk.

DPS avalanches are low probability and high consequence events. The likelihood of triggering a PS avalanche and the size of that avalanche can vary over a wide range. DPS avalanches are a specific creature, very large in size and hard to trigger.  We look for three things before we add it to our list of Avalanche Problems. Those three things are:

• Avalanches will be  stubborn to trigger,  Unlikely or Possible on the Likelihood scale
• Avalanches will be destructive,  D3 or larger
• Avalanches will break on deeply buried or basal weak layers

These criteria capture the low-probability/ high-consequence nature of DPS avalanches.  A low Likelihood means there will be very few or no natural avalanches, human-triggered avalanches will be unlikely, and large explosive and cornice triggers will only produce some results (ADFAR2).  A D3 (Very Large) avalanche could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few trees. When the likelihood slider drops towards “Unlikely” and the size slider climbs to “Very Large or Historic”, we have a DPS avalanche problem (see image below).

DPS avalanches are especially scary because most people don’t have much experience dealing with them.  It is hard to gain experience dealing with these beasts because we don’t see DPS avalanche cycles that often. In a typical year we could see over twenty cycles of Storm, Wind, and Persistent Slab avalanches, but we may only see one DPS avalanche cycle in five years.  You could navigate through two Storm Slab avalanche cycles in a week of touring, but it could take you ten years to gain the same amount of experience with DPS avalanches. These avalanches are also very large and extremely dangerous. Most people that get caught in one get killed.  This makes it very difficult to learn from a close call. Your first encounter with a DPS avalanche could very well be your last.

Over the last 15 years, almost all avalanche accidents in Colorado where more than one person died were the result of a DPS avalanche. In two seasons with pronounced DPS avalanche cycles (2008-09 and 2012-13), DPS avalanches accounted for more than 60% of the avalanche fatalities.  In the figure below (covering two seasons: 2012-13 and 2013-14) you can see that avalanches involving persistent weak layers are particularly dangerous. DPS avalanches only accounted for 5% of the observed avalanches, but caused 42% of the fatalities.  Sure sounds like low-probability/high-consequence, doesn’t it?  You can read the whole study here.

In a year with DPS avalanches we can describe the forecast zones where they could happen and the aspect and elevation of the slopes that are most likely to produce one. This is the good news. The bad news is that if you have ten of those slopes, it is really hard to predict which one will produce a DPS avalanche. This is the low probability part. Remember the other half of the description is high consequence. Because DPS avalanches are so dangerous, the only safe way to manage your risk is by avoiding those suspect slopes. On a bad year, you might have to avoid those slopes for the rest of the season. This can be hard to do because people will test suspect slopes, and most will get away with it (they are low-probability events). And due to the nature of a DPS avalanche problem the danger is almost always MODERATE (Level 2) when this is our main avalanche problem, because these avalanches are hard to trigger. That combination -people testing slopes without immediate consequences and a MODERATE (Level 2) rating – doesn’t scream “dangerous” the way an avalanche warning does.

So where are we this year?  In some places we can produce D3 avalanches, as demonstrated by the mid-December avalanche cycle.  Between December 14 and 21, multiple D3 avalanches released in the Aspen, Gunnison, North San Juan, and Front Range zones. This includes both natural and human-triggered slides.  Around half of these avalanches ran naturally during and shortly after the storm cycle. So while we met the size criteria, we weren’t at the point where we called these avalanches stubborn to trigger. Instead, we had Likely to Very Likely, and Large to Very Large PS avalanche problems. This resulted in avalanche warnings and HIGH (Level 4) danger.

The likelihood of triggering PS avalanches in these areas has since decreased, but some notable D3 avalanches released post storm.  A narrow escape near Crested Butte, a very large avalanche triggered by a snowcat near Loveland Pass, and explosive triggered slides north of Berthoud Pass, and very large avalanche with an unknown trigger near Cameron Pass have us talking about if a potential DPS problem is in our future.

It is getting harder to trigger an avalanche that breaks into the weak snow near the ground in most of the forecast zones. So the Likelihood of triggering a Persistent Slab avalanche in decreasing. We have seen Very Large (D3) avalanches in the Aspen, Gunnison, North San Juan, and Front Range zones.  Most of these zones have a deep enough snowpack to produce more Very Large (D3) avalanches.  The Sawatch and Vail/Summit zones picked up less snow during the mid-December storms. Most of the avalanches in these zones have been large enough to kill you (D2), but not large enough to destroy a vehicle or timber structure (D3).We have a basal weak layer, the avalanches are getting harder to trigger, and in some zones they getting quite large. Although we have not started to warn people about DPS avalanches, some of the PS avalanches are getting larger and harder to trigger. The weather over the next couple of weeks will determine if we are just going through a scary period, or if we’ll move into a DPS cycle that lasts the rest of the season. For now, remember that we’ve seen some tricky conditions over the last few weeks and there is no indication they are over. Please read the forecast before you go out and keep in mind that this kind of Moderate (Level 2) danger includes some pretty big avalanches.

Stay safe out there and enjoy the snow!  Happy New Year!

Click here to learn more about Avalanche Problems from the USFS National Avalanche Center.

By Nick Barlow

One of the most useful resources provided on the CAIC webpage is the weather stations page (Observations > Weather Stations). Here you will find a table of hourly and archived observations from a large network of weather stations throughout Colorado, sorted by forecast zone and elevation.

A screenshot of the CAIC Weather Stations Page

The several highlighted columns report different quantities of precipitation. For SNOTEL stations, up to seven different readings are given. Below is a description of these readings, the instruments that take them, and how the data can be useful for backcountry users.

Snow Water Equivalent (SWE)

SWE is the total amount of water contained in a fixed sample of snow. More simply, it is the resulting depth of water if the entire sample melted. In this context, “sample” could mean the entire seasonal snowpack (SWE), or just new snowfall over the past 24-hours from a single storm (SWE24). Seasonal SWE is particularly useful for long-term hydrological applications, such as forecasting water supply or seasonal runoff. For example, water managers use the data to determine how much water is stored in the mountain snowpack for the warmer months ahead. This is the primary function of the SNOTEL network, and the strategic placement of stations in important water basins throughout the United States. Yet SWE is also relevant for backcountry users.

The density of water varies only slightly with temperature. By contrast, snow density varies significantly from storm to storm. The SWE calculation is a way of standardizing snowfall for use in further applications. When we think about loading weak layers in the snowpack, calculating SWE can be of great value. The data can reveal the load added to the snowpack from an individual storm.  By comparing SWE to snow depth, we can also discern whether the storm snow was dense and heavy vs. light and fluffy.

At SNOTEL stations, SWE is measured using snow pillows: large 3-meter x 3-meter bladders (steel and rubber) installed on the ground and filled with a volume of antifreeze. As snow accumulates on top of the pillow throughout the winter, instruments measure the increasing hydrostatic pressure upon the liquid. With that, the mass of the overlying snow is calculated.  Knowing the density of water allows us to calculate SWE. A snow depth measurement allows us to calculate snow density.

Snow pillow and depth sensor

Measuring Snow Depth

Snow depth is perhaps the easiest quantity to measure, simply by using a ruler or avalanche probe. It is more complicated at remote weather stations with the automated measurement and logging of data.

At SNOTEL stations, an ultrasonic depth sensor mounted above the snow pillow measures the snow depth. The sensor sends a signal downward towards the ground and measures how long it takes the signal to bounce off the snow surface and return to the sensor. Knowing how fast the signal travels, a properly-calibrated sensor will give an accurate reading of snow depth.  On the weather station page, there is a field for changes in depth over a 24-hour period (Sno24), in addition to the total depth of the snowpack (SnoHt).

The ultrasonic sensor is also useful for backcountry users. Most simply, it is the only tool at a SNOTEL station that can tell you how much new powder you’ll find on any given day. However, you can glean more, and more important information from a SNOTEL site.

For one, the total depth of the snowpack can be particularly useful. A shallow snowpack can promote changes in snow structure, and create persistent weak layers. This is important information to gather before traveling into the backcountry. On a shorter time-scale, the amount the snow depth increases in a single storm is a good estimate of how much snow is available for wind transport. We can also estimate the depth of new Storm Slab or Wind Slab avalanches, and at what depth we might find the old/new snow interface in our snow pits.

Measuring Liquid Precipitation

SNOTEL stations are equipped with a precipitation gauge to measure liquid for the entire water-year. During the warmer months, rain simply falls into the gauge. The gauge then measures and logs the data automatically. Snow also falls into the same gauge during the winter months. However, sub-freezing temperatures would make any kind of liquid measurement essentially impossible. To combat this effect, SNOTEL precipitation gauges are “charged” with a volume of propylene glycol, melting the snow on contact as it falls into the gauge. The gauges also contain mineral oil, designed to sit on top of the collected liquid and prevent evaporation over time. On the weather station page, data is in 1-hour (Pcp1), 24-hour (Pcp24), and since-midnight (PcpAc) format.

Liquid precipitation gauge

For backcountry users, liquid precipitation data can also be useful. Ideally, data from this gauge would match the calculated SWE data from the snow pillow and ultrasonic sensor. This is not always the case. It’s important to recognize the differences and primary functions of each piece of equipment. Data from the liquid gauge is used for seasonal purposes. The gauge keeps measuring precipitation long after the snow melts away from the snow pillow.

However, the data can be used in conjunction with the SWE and snow depth in order to provide a more well-rounded answer to what is going at the station. An example would be for rain-on-snow events.

Snow pillows may not always capture added SWE from rainfall, as some of the liquid may channel away from the pillow. In this case, the liquid gauge is the only piece of equipment that could tell us if rain-on-snow has occurred. A simultaneous temperature reading from the SNOTEL could also reinforce our suspicions.  

Takeaway

Remember that automated SNOTEL stations exist in remote mountain locations. The stations use three different pieces of equipment to measure precipitation, and each piece has its own unique purpose for being there. Like any equipment, the gauges are prone to both random and systematic errors, and the data may not always be trustworthy.

A variety of issues can (and do) arise at SNOTEL stations. For this reason, they require continued maintenance and quality control of the data they output. This can be exceptionally difficult during the winter months, as access to many of the stations is difficult.

As backcountry users, we should analyze each piece of data individually before forming a conclusion about what has transpired. Compare the different forms of output (SWE, depth, melted liquid) and attempt to read between the lines.

Also, recognize the data is from a single point, and may not be representative of the entire area in which you’ll be traveling. Of all meteorological surface measurements, precipitation is by far the most spatially variable. You will likely find inconsistent snowfall results within different elevation bands and aspects as well. Study the data from other near-by stations; learn which stations typically receive more or less snowfall than others.

Most of all, be thankful the SNOTEL network exists. It is a wonderful tool to have at our disposal. These stations shed light into the dark and cold, providing us with vital information at just a mouse-click away.

Overview of precipitation quantities

As of March 1, avalanches have killed 23 people in the United States this winter. This is the second largest number of cumulative fatalities through February since the winter of 2000-01. Unlike January 2016, the six avalanche deaths in February 2016 were typical for the month (median 6). Typically, about 60% of avalanche fatalities for the winter have occurred by March 1. Projecting forward, 2015-16 could be one of the worst winters for avalanche deaths in recent years. This is a rough estimate, and how the snowpack evolves over the next few months will determine the number of serious avalanche accidents.

The chart below shows cumulative fatalities by month for avalanche years 2001 through 2015 in gray. Median, first, and third quartiles are shown in blue. The cumulative fatalities for 2016 are in red. Mouse over the chart for monthly values.

[Updated February 3, 2016] As of February 1, there have been sixteen avalanche accidents resulting in fifteen fatalities across the US this winter.  Thirteen of the deaths occurred in January 2016,  with ten of them occurring in the span of nine days between January 16 and 24.  Two of the fatalities occurred in Colorado. This is a very large number of fatal accidents in a relatively short period. We can look at previous winters to see how unusual this cluster of accidents is. Unfortunately, the answer is “unusually bad.”

Since 1950, January is the month with the most avalanche fatalities. The 12 fatalities in a single month is the largest number of fatalities in January since 2008, when 19 people died in avalanches. The winter of 2007-08 was one of the worst seasons for avalanche fatalities in the last 65 years.

In the last 15 winters, February has taken a slight lead, with 22% of the total fatalities compared to 21% in January. During that period there have been between 2 and 6 fatalities in January. In addition to January 2008, only February 2014 (12 fatalities) and February 2012 (13 fatalities) had similar numbers of avalanche deaths within a month. The 2011-12 and 2013-14 seasons were also among the worst seasons for avalanche deaths in the last 65 years.

Total avalanche deaths by month, winters 2001-2015. The red line indicates the average of cumulative fatalities through the season.

Avalanche deaths by month, winters 2001-2015. The red “x” mark median values.

In the United States, about 70% of fatal avalanche accidents occur within four days of a prior accident (Logan and Witmer 2012). These clusters results in long accident-free periods, then a period with several accidents, followed by another long accident-free period. Within a cluster, it can feel like an unusually high number of accidents.

The statistical analysis does not reduce the pain and loss with each fatality. Each one leaves a hole in the heart of the victim’s family, friends, and community. The analysis does help us place current tragedies within a longer context. There have been an unusual number of accidents recently. This may be an indication of how accident patterns will evolve over the rest of the winter.

As I touched on before, language that minimizes close calls can reinforce overconfidence and an illusion of skill. A close call doesn’t count or isn’t that serious, because it’s an exception, because nothing really happened. It must be our abilities that made the difference. And with these abilities, we can take more chances.

I’ve wondered how to break that cycle. Recently, I heard how it happened for a friend and occasional ski partner. We were talking while skinning on a mild day. He’s had at least three close calls, two of them involving large avalanches. He’s never seemed to shrug off the incidents, and he takes avalanche safety seriously. But still, the hits just keep on coming. Enough so that he and his frequent partners earned the nickname “The Wrecking Crew.” The most recent involved a small avalanche earlier this season.

I was surprised to hear that he’d hardly skied in the backcountry since then. I figured it was just conditions. “No,” he said, “it was like a switch got flipped. Suddenly it just seemed so risky.”

The defining incident had happened early one morning, on what was supposed to be a casual one-n-done with some of the Wrecking Crew. The group had an inconclusive discussion about a line down the bowl, with at least one member of the group arguing that they stay away from the bed surface of an older slide. It had been reloaded with new snow and a few days earlier someone had triggered a second, smaller slide that released the new snow on the other side of the bowl. My friend watched the first skier nonetheless turn into the old bed surface and trigger a small slide that briefly knocked him off his feet. He recovered and escaped out the side.

Several things made this incident feel different for my friend. The skier who triggered the slide was recovering from knee surgery. My friend said that while he watched the skier struggle with the debris, “I kept thinking about his knee and how it would suck for him to get hurt again.”

This incident was also more of a surprise, unlike the previous ones, when he knew he was pushing the line and far more prepared for something to go wrong. “It was supposed to be a casual day. We weren’t really going to be exposed to much danger. The terrain and the danger were moderate. Yet something still happened. I realized it could happen anytime.”

The big thing, though, was a conversation with one of the others in the group when they arrived back home. “We looked at each other at about the same time and said, ‘That was not ok, was it?’ And it was like waking up after one too many frat parties.”

My friend and I had a good tour together that day. I didn’t ask him if skiing in avalanche terrain felt different this time. I don’t know that there’s a recipe for replicating his come-to-Buddha moment. I do see some elements that seem common to people who aren’t overconfident: a visceral sense of the consequences of a slide, an awareness that avalanches are unpredictable and ultimately unmanageable, and lastly, a willingness to listen to friends who don’t write off close calls.

blase reardon

A recent conversation illuminated how people can perceive the risk involved in their decisions and actions very differently than others do.  The subject was driving skills, but it could just as well have been backcountry travel. I’ll paraphrase the conversation, and I have slightly altered and exaggerated some details in the interest of making a point.

The conversation was prompted by a comment that a friend wouldn’t have to speed on her morning commute if she left home 15 minutes earlier. She offered a spirited defense of her driving. “Speed limits are suggestions. There’s no need to drive less than 5 mph over the speed limit if there’s no inclement weather. People that drive less than the speed limit are dangerous.”

Her audience wasn’t buying it, so she escalated her defense. “I’m a good driver. I’ve only had one wreck. And that was because of black ice.” The car incurred damages of $10000, but she only paid the deductible, so it didn’t count as a serious accident in her mind. “And two tickets.”, she added.

It came out that she’d only learned to drive in 2009. A listener pointed out that three incidents in five years was a pretty high rate of getting into trouble. She argued that the second ticket shouldn’t count, as she was speeding to pass a semi. “Don’t you think that driving next to a semi is unsafe?” she asked the trooper. She threw in that it was her birthday, but he gave her a ticket anyway. “I couldn’t flirt my way out of it, like I had other times.” The “other times” were three more traffic stops in which she hadn’t gotten a ticket. That meant a rate of more than one incident for each year of driving.

“That’s not bad. I’m a good driver.” Someone noted that some people go their whole lives without a ticket or an accident. “They’re probably the people going 10 mph below the speed limit and making it dangerous for everyone else.”

She then told a story about driving 100 mph on I-70 in a borrowed Audi because the car is designed to hold the road better at high speeds. She offered to drive anyone home. There were no takers.

My friend seemed to feel that deft car-handling skills equate to safety. Many of her defenses sound familiar; I’ve heard similar sentiments in conversations about skiing and riding in the backcountry. Somehow, the unintentionally-triggered slides and the near misses don’t count because of some circumstance specific to that incident. They become confirmation of skills rather than lessons. An avalanche flank 15 feet from your track isn’t a close call; it’s proof you knew how to pick your line. Flawed conclusions like that are easy to draw in a wicked environment like the backcountry, where irregular feedback promotes learning the wrong lessons from our experiences, and encourages an illusion of skill.

I don’t know whether my friend drives as recklessly as she sounded in that conversation. Nor the balance of over-confidence and expertise of anyone I meet in the backcountry. I do know I aim to second-guess my own claims to expertise and skill. I try to imagine what they’d sound like out of context, after an accident perhaps. Andre Roch ‘s famous quote, purportedly made after one of his own near-misses, applies here: “The avalanche doesn’t know that you are an expert.” It’s the quality of situation-specific decisions that matters. And every close call counts. The backcountry doesn’t offer a good-driver discount.

blase reardon

Blase Reardon

On January 17th, 2014, a pair of riders triggered a large avalanche on a steep, near-treeline slope in the backcountry behind Snowmass Ski Resort. The slope had previously been nicknamed “Mr. Magoo’s” after a ski patroller who sometimes acted like the near-sighted cartoon character. The riders escaped unhurt, despite an ugly terrain trap below. An hour later, the resort’s snow safety director watched a solo skier turn down the same slope and trigger a second slide adjacent to the first. He met the solo skier as he returned to the resort and asked him whether he’d seen the first slide—or the larger natural avalanche just up the drainage at the same aspect and elevation. The solo skier replied, “It’s okay; I have skied Silverton and I skied the path a couple of years ago.”

The slope where the January 17th incidents occurred is steeper than 35 degrees and faces southeast. On that day, it was blanketed with a foot-thick slab formed by a recent storm and subsequent cross-loading; the slab sat on a thin, persistent weak layer. It was a slope that closely fit a pattern of recent avalanche activity and that was highlighted in the CAIC forecast as the kind of slope where people were most likely to trigger slides. With the danger rated as Considerable, skiing that slope on that day was a risky proposition, especially alone and with a fresh slide visible.

The solo skier didn’t answer the question posed to him – did he see the other slide and, implicitly, was he concerned about avalanche danger on the slope? Indeed, he seemed to answer a different question altogether, one centered on skiing rather than avalanche conditions. Perhaps standing at the top of Mr. Magoo’s he asked himself, “Can I ski a slope like this?” And his answer seems to have been “Yes, because I’ve skied slopes this steep before. I’ve even skied this slope before.”

According to Nobel-prize winner Daniel Kahneman, substitution like this is a nearly automatic cognitive response to complex, irregular environments. Our brains produce what Kahneman calls “off-the-shelf answers” to difficult problems by answering simpler, more familiar questions. It’s a sub-conscious process, and it provides solutions that leave us feeling very confident in our assessments and choices. Assessing the risk of triggering a slide on a steep slope covered with new snow is a complex task, fraught with uncertainty. Faced with that, our brains quickly default to questions with simpler answers, like “Can I ski this slope without falling?” or “Will the skiing be as good as it looks?”

Marketing provides numerous everyday examples of this pernicious tendency. When faced with a question like “Is this the best pair of skis for me to buy?” we often answer a question more like “Do I like this brand of skis?” or “Do I like the graphics?” In situations like these, substitution often provides adequate answers, because the alternatives aren’t that different and the consequences of not answering the initial question aren’t severe. And substitution has the advantages of saving us mental energy and time. Once we’ve substituted a simple, seemingly coherent answer to a complex question, we can confidently summon numerous arguments supporting our choice without recognizing the substitution.

That leads us back to Mr. Magoo, the cartoon character referenced in the slope’s nickname. Mr. Magoo stubbornly refuses to recognize his near-sightedness. He doesn’t have to, because situations always work out for him. Magoo mistakes an airport for a movie theater, takes a seat on a departing plane—”It’s like I can feel the plane taking off!”—wanders around on the wings, unknowingly leads the police to a bank robber, and when the plane lands, tells the flight attendant he really enjoyed the film. The tension in the Mr. Magoo cartoons derives from seeing how lucky the character can get yet be oblivious to the dangers he’s facing, thanks to his near-sightedness . They’re funny because we know his luck will never run out.

We can all be Mr. Magoos in the backcountry. When nothing bad happens, it’s easy to finish a day of skiing or riding in avalanche terrain feeling confident we made good choices. So it’s easy to take the wrong lessons from our experiences. We’re sure we really liked the movie, unaware of how close we came to falling off the wing. The three riders involved on the slides on January 17th might easily conclude that they judged conditions correctly. More correctly even than the forecast, which called slopes like Magoo’s dangerous. None of them were hurt. The answer of “Yes, I can ski this” seemed to work, so the solo skier might be more likely to rely on it the next time he’s faced with a slope where the stability is questionable.

The winter backcountry is no cartoon, however. Substituting an easy question for the relevant one can kill our friends, our loved ones, or us. Our luck can run out. Or we may not get lucky at all. It’s what Kahneman and others have termed a “wicked environment”—an environment in which a lack of regular, reliable feedback allows us to develop habits and patterns based on faulty correlations, or luck.

So, what’s the alternative, given our brain’s hardwired proclivity for substitution and the wicked nature of the backcountry? How do we keep from being Mr. Magoo?

The avalanche on Magoo’s

In previous section of this article, I noted that the winter backcountry is an instance of what Nobel-Prize winning researcher Daniel Kahneman and others describe as a “wicked environment” for developing expertise. In part, that’s because expertise in the backcountry is a collection of skills. We have to master the individual elements—technical skiing and riding skills, route-finding, and stability assessment among them—while simultaneously learning which items in the set to prioritize and apply in a given situation. It’s also because in the winter backcountry, we don’t get much immediate, consistent feedback on our decisions and actions. We rarely know how close we are to triggering a slope, so it’s easy to develop habits and patterns based on faulty correlations, or luck.

A real-world example of the rarity of immediate feedback in avalanche terrain surfaced a few years ago, in a video posted on YouTube that’s since been pulled. It showed a skier finishing a run on Puckerface, a steep slope near Jackson Hole Mountain Resort. The soundtrack includes lots of whooping. Then a title card appears, reading “Second Run. 10 minutes later.” A snowboarder starts down the same face, and makes a hard first turn. The entire slope fractures several feet deep, and slides. The snowboarder claws into the bed surface and stops. The camera shakes and jerks, accompanied by lots of cursing. The snowboarder walks away on the ridge. The video shows the slide a second time, in slow motion.

Let’s put ourselves in the boots of the first rider on Puckerface on January 2, 2012. We choose to ride the  slope for some reason—maybe a well-considered assessment of stability, maybe by substituting a question that’s easier to answer, like whether there’s enough sun on the face for good video. When it doesn’t slide, we conclude our rationale was correct. Given enough similar experiences, we could start to feel very confident in our skills. But the slide triggered by the second rider reveals a more accurate conclusion: we got lucky. And instead of developing skills, we might just be getting lucky, a lot.

Puckerface, just after the 2014 fatal avalanche. Photo courtesy Alex Do.

The image above also shows Puckerface on an early-winter day, this time nearly two years later, on Dec. 26, 2013. On this day, a rider wasn’t so fortunate; he was killed in the slide visible in the image. That’s the potential penalty for substitution, inadvertently relying on luck, or just plain making a mistake. Each day in avalanche terrain, each run or route we chose, is unique and novel; we have incomplete or ambiguous data, we get one chance, and the cost for choosing badly can be fatal.

An alternative to relying on luck is expert intuition—distinguishing familiar cues in a new situation and choosing an appropriate response. As Kahneman notes, “Expert intuition strikes us as magical, but it is not…[It] is nothing more and nothing less than recognition.” It’s Mr. Magoo with eyeglasses, a prescription that lets him recognize an airplane instead of confusing it for a movie theater. In his classic essay “The Ascending Spiral”, pioneering snow scientist Ed LaChapelle echoes that point; intuition “is not some sort of extra-sensory perception.” He describes it as a “lifetime accumulation” of observations about snow, avalanches and weather. That doesn’t just happen, because the backcountry is a wicked environment. We help develop it by adopting simple habits that, over time, make the backcountry environment more regular and expand the base of stored cues necessary for expert recognition.

Below are examples of practices  that can improve the quality of our observations, our communication, and the feedback for our decisions.

It’s all about the up: Most—at least two thirds—of our time in the backcountry is spent going up. It’s our best opportunity for observing and communicating. It’s also when most miscommunications and mistakes occur. Set a low-angle, meanderthal skin track that takes advantage of the terrain to investigate different aspects and slope angles, and that allows relaxed discussions of your observations without having to stop. Steep skin tracks make it hard to see much beyond your ski tips, and even if you do notice something important, it’s hard to communicate it when you’re anaerobic. If you’re breaking trail and can’t hear the group behind you talking, your track is too steep for easy observations and communication.

Give it a rest: Take breaks at decision points. Fiddling with your clothes or gear randomly just slows you down yet provides little information about snow conditions or route choices. Stopping to drink, eat and layer up when you’re faced with a decision is productive; it allows you to look around when you’re comfortable and talk about what you see. More often than not, you’ll pick up nuances in the terrain that you didn’t see while moving and out of breath—as will your partners. And you’ll make better decisions when your brain isn’t starved for oxygen or nutrition. Pace your group so you’re moving steadily and don’t feel rushed when you stop at decision points.
You are not the Captain now: Encourage feedback within your group. You’re looking for ideas that can save your ass, not aiming for agreement. It helps to rely on questions rather than declarations. “Does that side of the slope look wind-loaded?” instead of “Most of the slope isn’t wind-loaded.” Listen for contrarian opinions rather than trying to silence a squeaky wheel. Acknowledge that anyone in the group has veto power.

Write it down: Keep a field notebook or submit observations to your local avalanche center after each backcountry trip. It’s a sure way to notice and remember details about snow and weather conditions.. Summarizing them for a field report forces you to make sense of what you observed, to sort what’s most important from what’s irrelevant. And it gives you something besides dim memories when you’re checking impressions of past events.
Debrief: When we talk about a day in the backcountry immediately afterwards, we often focus on the highlights—the great run, the funny fall, the beautiful light or snow. You provide otherwise unavailable feedback on your decisions by including an opportunity to talk about how you did things and whether those actions put you at risk. Guides often do this formally, in afternoon meetings in which they can identify when they were most at risk during the day. A friend’s more informal approach, is to ask, “Well, did we get it done, or did we get away with it?” Find a way to expand your end-of-day conversation to more than high fives. If something nags at you a day or a week later, talk with your partners so everyone understands and learns from the experience.

Find a mentor: Years ago, I spent a day traversing a high peak in the Wasatch with a mentor when the avalanche danger was high.  It was a lesson in micro-route-finding. Near the end of the day, when it seemed we’d mostly passed the hazards, I took a few extra turns on a small slope I now recognize as a terrain trap. I looked up to see my mentor giving me a look that said, “That. Was. Dumb.” That look still floats into my consciousness when I encounter similar slopes. Though the look clearly communicated stupidity of my move, it was much more forgiving feedback than triggering the slope. Or another like it, because without that mentorship I might have gone much longer without learning to take small slopes seriously. You learn from (and with) a mentor in an iterative process, the goal of which is your becoming equally skilled and knowledgeable, perhaps more so, than your mentor. This relationship is different than that with a guide, who may pass on some useful tips but who is a leader.

Others with extensive expertise in the backcountry can offer up other practices like these, which may work better for them or better period. The point is less the specific habits than making an effort to maximize the quality of our decisions and the feedback we get for them, so we have the best chances of seeing our Mr. Magoo-like close calls and learning from them, without the too-painful learning that comes if our luck runs out.  Time in the backcountry with that kind of reflection is what leads to the lifetime of accumulation and instant recognition that Kahneman and LaChapelle identify as expertise.

2 years ago I was traveling in India with Water For People. I was lucky enough to spend time with my amazing colleagues, who really opened my eyes to the importance of ownership, co-investment, and public-private partnerships. My colleague from across the world, Satya, and I walked through one of the poorest communities I have ever seen, and we discussed why this community was flourishing. Water For People had catalyzed the relationship between the State government and the people of this community. Water was flowing, and a public-private partnership had been developed to ensure that it continued to flow in the future. The community invested in their water system and the sustainability of it. They invested in something they wanted and saw a need for.

6 years ago, I started fundraising for the Colorado Avalanche Information Center. I read about a chain of events that was going to cost the center $25k in funding. My initial thoughts about what was happening were negative and also incredibly unproductive. However, my second thoughts, and a discussion with a friend, made me realize that I can help. This is our avalanche center, and we can’t afford to see it lose any funding or decrease the backcountry forecast operations in any manner. This one article 6 years ago is what started the CAIC Benefit Bash, an event that now raises $100,000 annually to go toward avalanche forecasting and education throughout the State of Colorado. Then I was a volunteer. Today, I am the Executive Director of the Friends of CAIC and asking you to help us reach our fundraising campaign goal of $150,000.

The Colorado Avalanche Information Center’s Backcountry Avalanche Forecasting program is small but mighty. The program has grown over the past 10 years but with only 6 forecasters operating in 10 zones, we still have a long way to go to provide the service needed by the backcountry community. Colorado is a very big place and there are more and more people enjoying the State’s spectacular winter backcountry each year. Our goal is to provide the best avalanche center in the country. To achieve this goal we need everyone’s support. The State of Colorado is incredibly supportive and has increased the CAIC’s funding this last legislative session. But to really expand, we need every user involved as well. This partnership is the best way we can grow the CAIC’s backcountry forecast program, and I am personally asking you to support avalanche forecasting and education throughout the State of Colorado.

This is your avalanche center and to ensure we continue to have the best avalanche center in the country we need your help. These public-private partnerships are solving the world’s toughest problems. We have developed the same model to create the best avalanche forecast center in the United States.

Join us by donating here: http://www.crowdrise.com/StayInformedStayAlive

Aaron Carlson
Executive Director
Friends of CAIC

We tend to think about hazard on a spectrum of both likelihood and consequences. The likelihood that a given incident will occur can range from low to high. If an incident does occur the resulting consequences could range from low to high. An example of a high likelihood low consequence event is when you forget to put on sunscreen and you get a sunburn. Similar to likelihood is the frequency at which an event might occur. A high frequency event is one that we often have lots of experience with. Take driving for example. Most of us drive all the time, sometimes at very high speeds and on treacherous mountain roads. But how often do you get in a car accident? This is a high consequence activity that we have lots of experience with and generally can manage to do safely.

So what does this have to do with avalanches? As backcountry travelers our level of experience, training, and the systems that we employ can determine our ability to effectively choose appropriate terrain for the conditions. Backcountry travelers with decades of experience have seen many high frequency or high likelihood events over the years. Novices who have been traveling in the backcountry for only a couple years may have little experience with even the high frequency events. We generally do a good job at making decision in situations that we deal with on a regular basis. Examples of a high likelihood lower consequence problems are Storm Slab avalanches and Loose Dry slides or sluffs. Even on the high likelihood high consequence end, experienced travelers are still pretty good at making decisions. Take for example Persistent Slab avalanches during an active cycle. For someone who only has only a few years of experience this situation may sound terrifying and unmanageable. The best options for this person may be to avoid avalanche terrain in the backcountry. A backcountry traveler with many years of experience and training in these same conditions can understand the nuances of the problem, plan out an appropriate route that minimizes exposure to terrain prone to this avalanche problem, and effectively facilitate their group in making decisions that will keep them safe. It’s important to have an awareness of your experience level with different situations and recognize when you are dealing with conditions in which you are inexperienced.

Low likelihood high consequence situations are challenging to both novices and seasoned veterans. Currently most forecast zones around the state are dealing with avalanche problems involving deeply buried persistent weak layers that are difficult to trigger. If you do manage to hit the right spot and trigger one of these Deep Persistent Slab avalanches, the result could be a very large slide. This low likelihood high consequence situation is scary stuff. A resulting avalanche from these conditions is something that we don’t often experience and would leave little chance for survival. Last year’s Ptarmigan Hill and Sheep Creek accidents occurred during similar conditions. As backcountry travelers, we are bad at “managing,” or making decisions, in these kinds of conditions. We don’t have much experience with them and when we make a mistake the consequences are grave. We can easily be lulled into confidence and complacency when we don’t see signs of instability or recent avalanches. It’s important to remind ourselves of the consequences of the current conditions and our inability to “manage” them. Strive for conservative terrain selection, giving your group a very wide margin for error. Go to areas where you are confident that your group can make sound decisions and select appropriate terrain to stay safe.

–Josh Hirshberg