• Backcountry Avalanche Forecast
  • Forecast Discussion
  • Observations & Weather Data

Sun, Apr 16, 2017 at 6:16 AM
Issued by: blase reardon

Today

 

Tomorrow

Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.   Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.   Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.   Low (1) Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
  Danger Scale

  • No Rating
  • 1
    Low
  • 2
    Moderate
  • 3
    Considerable
  • 4
    High
  • 5
    Extreme

Summary

After clear skies and almost 8 hours of sub-freezing temperatures last night, you can expect a solid and lasting re-freeze of the surface snow this morning. That means a wide window for safe and straightforward travel before Loose Wet avalanches become a threat. You can stay ahead of this problem by timing your travel to start on easterly slopes and end on westerly slopes. Pay close attention to changing surface conditions through the day. If turns on steep slopes start releasing small sluffs, it's time to make your way to an exit. Dangerous conditions may be developing if stepping off your skis, boots or sled drops you into the snow deeper than the tops of your boots. 

This is our 144th and final zone backcountry avalanche forecast for the 2016-17 season. Starting this afternoon, we will issue statewide avalanche summaries each Sunday, Wednesday, and Friday through the end of May.

We have made impressive strides in our mission of avalanche forecasting and education here in Colorado. Help us continue that trend and donate to the Friends of CAIC fundraising campaign. https://avalanche.state.co.us/donate/.

 

Recent Tweets

@CAIC: Solid freeze->wide window b4 Loose Wet avs a threat. LOW(L1). Thanks 4 all obs & support through winter! Apr 16, 6:22 AM
@CAIC: LOW (L1) It's Spring and it's warm Avoid steep slopes when the sun is on them. Get out of the mountains early. Apr 15, 5:19 AM

Avalanche Problem

 
problem icon
N
S
E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
Likely
Possible
Unlikely
Historic
Very Large
Large
Small
Avalanche Character Aspect/Elevation Likelihood Size

What You Need to Know About These Avalanches


Loose Wet avalanches occur when water is running through the snowpack, and release at or below the trigger point. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Avalanche Problem

 
problem icon
N
S
E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
Likely
Possible
Unlikely
Historic
Very Large
Large
Small
Avalanche Character Aspect/Elevation Likelihood Size

What You Need to Know About These Avalanches


Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas.

Avalanche Problem

 
problem icon
N
S
E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
Likely
Possible
Unlikely
Historic
Very Large
Large
Small
Avalanche Character Aspect/Elevation Likelihood Size

What You Need to Know About These Avalanches


Persistent Slab avalanches can be triggered days to weeks after the last storm. They often propagate across and beyond terrain features that would otherwise confine Wind and Storm Slab avalanches. In some cases they can be triggered remotely, from low-angle terrain or adjacent slopes. Give yourself a wide safety buffer to address the uncertainty.

Weather Forecast for 11,000ft Issued Wed, Apr 26, 2017 at 1:00 PM by Nick Barlow Statewide Weather Forecast
  Sunday Night Monday Monday Night
Temperature (ºF) 18 to 23 25 to 30 10 to 15
Wind Speed (mph) 10 to 20 15 to 25 5 to 15
Wind Direction W W WNW
Sky Cover Overcast Overcast Overcast
Snow (in) 3 to 5 3 to 5 0 to 2

Archived Forecasts

  • Select Forecast: Valid

Sun, Apr 16, 2017 at 7:02 AM
Issued by: blase reardon Statewide Weather Forecast  

Today marks the 144th - and last - Aspen zone backcountry forecast for the 2016-17 winter. Starting this afternoon, we'll publish statewide avalanche summaries each Sunday, Wednesday and Friday through the end of May. We'll continue to issue zone weather forecasts for 11,000 feet twice a day until the end of April.

Thank you to everyone who's contributed observations so far this winter. Special thanks to people who reported unintentionally triggered avalanches and/ or close calls. These are invaluable to other backcountry travelers, and they help us to confirm or fine-tune our forecasts. If you're out and about over the next six weeks, please let us know what you see. It doesn't need to be dramatic or technical; just report some basics information about where you went, what kind of slopes you rode, and what the snow was like. Alerting us to any recent or triggered avalanches can be especially helpful. 

A classic diurnal Springtime snow and avalanche cycle is underway and with no storms in sight, looks to continue for the next week or two. Mostly clear skies and up to eight hours of temperatures below freezing mean a solid, lasting refreeze of the near surface snow this morning. Surface crusts will soften as they receive direct sun and temperatures warm, and Loose Wet avalanches will become a concern by midday. These conditions will develop first on steeper, easterly slopes, then progress to westerly and northerly slopes.

The safest and best riding is when your skis or board sink less than an inch or two into the snow surface. Head for colder, shadier slopes if you're trenching into the snow or your turns are releasing small sluffs. Avoid being on or under very steep, rocky slopes if you see fresh rollerballs or fan-shaped point-releases. If you're punching through surface crusts, dangerous conditions may be developing. These are most likely above about 13000 feet, where recent warming and sun have only affected the near-surface layers of the snowpack and meltwater may be reaching older weak layers for the first time. Saturated snow can produce larger Loose Wet avalanches that gouge into older snow, as well as Wet Slab avalanches. It's easy to avoid these dangers by simply exiting this terrain early, before these conditions develop.

Stay alert for isolated slopes where more winter-like conditions are lingering. These are confined to shady slopes above about 13000 feet. These slopes may harbor old wind slabs and buried persistent weak layers under thin surface crusts. Rely on the tried and true signs of danger, like collapses and shooting cracks, so you can avoid triggering a small avalanche with outsized consequences.

The sustained warming is weakening cornices, and the potential for Cornice Fall avalanches is increasing. All too many avalanche fatalities occur when people ride or walk too far onto a cornice and it collapses, sending them down steep slopes below. Avoid this by staying off of and out from under overhanging drifts. 


  • Debris from a large natural Loose Wet avalanche on a SE-facing, below-treeline slope. This slide ran in late March, and exemplifies the kind of large wet snow avalanches that become more likely as temperatures remain warm and overnight refreezes are short and shallow. (full)
  • NE to E to SE facing slopes of Peak 12522 in Milton Creek drainage. Some Loose Wet activity out of the rock bands. Dust becoming apparent on surface. 4.12.17 (full)

See more photos & videos

Five Day Trend

Thursday

Friday

Saturday

Today

Tomorrow

danger icon danger icon danger icon danger icon danger icon
danger icon danger icon danger icon danger icon danger icon
danger icon danger icon danger icon danger icon danger icon

  • No Rating
  • 1
    Low
  • 2
    Moderate
  • 3
    Considerable
  • 4
    High
  • 5
    Extreme
Avalanche Observations
Report Date # Elevation Aspect Type Trigger SizeR SizeD
View Sun Apr 23 - >TL E WL AS / u R1 D1.5

See All Avalanche Observations

Field Reports
Report Date Observer Snowpack Obs Avalanches Media
View Wed Apr 26 Jeff Colt No No No
View Sun Apr 23 blase reardon Yes (3) Yes (1) No

See All Field Reports

Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Chapman Tunnel Wed Apr 26 2:00 PM 38 - - - - -
Independence Pass Wed Apr 26 2:00 PM 35 - - - - 4.0
Ivanhoe Wed Apr 26 2:00 PM 35 - - - - 2.0
Sunlight Wed Apr 26 3:00 PM 27 86 10 240 20 -
Mc Clure Pass Wed Apr 26 2:00 PM 36 - - - - -
Schofield Pass Wed Apr 26 2:00 PM 32 - - - - 1.0

See All Weather Observations