• Backcountry Avalanche Forecast
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Thu, Dec 13, 2018 at 7:02 AM
Issued by: Kreston Rohrig

Today

 

Tomorrow

Considerable (3) Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
Considerable (3) Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
Considerable (3) Dangerous avalanche conditions. Cautious route-finding and conservative decision-making essential.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
  Danger Scale

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    Low
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    Moderate
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    Considerable
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    High
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    Extreme

Summary

Up to 10 inches of new snow has raised the danger level and the risk for you to trigger an avalanche. Reports of widespread Surface Hoar pre-storm on most aspects around Buffalo Pass are now buried by the new snow. This dangerous weak layer will increase your chances of triggering an avalanche on steeper slopes and convex terrain features where you deeper accumulations of new snow are present. Shooting cracks from your skis or snowmobile are a clear sign that this problem is around you. The consequences and size of the avalanche you can trigger will be proportional to the size of the slope you are on. Even on small slopes, an avalanche triggered in the new snow may not be large enough to bury you but could push you down into the trees or off a cliff.

At higher elevations of in open wind-effected terrain, the new snow will continue to drift into deeper, thicker slabs. You can trigger larger avalanches in these areas that may break into older weak layers potentially wiping out the entire season's snowpack. Cautious route finding and conservative terrain choices are essential today to avoid being caught in an avalanche. Stick to slopes less than 30 degrees well clear of steeper terrain above you to reduce your risk.  

 

Avalanche Problem

 
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N
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E
W
NW
NE
SE
SW
Above Treeline
Near Treeline
Below Treeline
Certain
Very Likely
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Possible
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Historic
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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.

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


Storm Slab avalanches release naturally during snow storms and can be triggered for a few days after a storm. They often release at or below the trigger point. They exist throughout the terrain. Avoid them by waiting for the storm snow to stabilize.

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 Thu, Dec 13, 2018 at 12:06 PM by Spencer Logan Statewide Weather Forecast
  Thursday Night Friday Friday Night
Temperature (ºF) 0 to 5 22 to 27 10 to 15
Wind Speed (mph) 5 to 15 5 to 15 5 to 15
Wind Direction W W SW
Sky Cover Clear Mostly Clear Partly Cloudy
Snow (in) 0 0 0

Archived Forecasts

  • Select Forecast: Valid

Thu, Dec 13, 2018 at 7:28 AM
Issued by: Kreston Rohrig Statewide Weather Forecast  

The avalanche danger has elevated to Considerable (level3) in the Steamboat and Flat Tops zone but should include areas around Cameron Pass as well. Accumulations of up to 10 inches of new snow will increase the likelihood for you to trigger and get caught in an avalanche today. In many areas across the northern mountains the new snow has fallen on a mixed bag of weak snow surfaces. 

The more serious concern is that a small avalanche may have enough mass to trigger the more deeply buried weak layers. These avalanches are now breaking 4 to 5 feet deep. Even without a small avalanche in the surface snow, you can trigger one of these Persistent Slab avalanches all by yourself if you find the wrong spot. These are localized shallow spots in the snowpack, like along slab margins, and in rocky areas. avoid these and reduce your risk. 

Ongoing reports of weak snow and human-triggered avalanches are clear evidence of these looming problems. Observers reported collapsing in the Winter Park and Byers Peak areas of the Front Range. In the Butler Gulch area, observers reported ECT's failing upon isolation on near-treeline east-facing terrain. Over in East Vail, a skier triggered this slide on steep northeast facing slope on Monday. And up in Steamboat, were getting reports of collapsing and worrisome snowpack results.

That's pretty solid and widespread evidence that the threat of triggering a large and destructive avalanche breaking on persistent weak layers buried by mid to late November snowfall is alive and well.

For the near future north and east-facing terrain is most dangerous. Stiffer, thicker, and more continuous slabs overlying more widespread weak layers. But don't let your guard down on other aspects. If the slope looks wind-loaded, or you can see the snowcover spanning enough terrain that a large slab is possible, check and see if there are buried weak layers under a stiffer slab before venturing into steeper terrain. 


  • Small skier triggered avalanche near Vail Pass 12/7 (full)
  • Mt. Baldy, southeast aspect. SS failed on top of the Thanksgiving crust, leaving a smooth white bed surface. (full)
  • Looking North across fracture line, 2 different start zones (full)
  • ASr triggered from adjacent low angle terrain (full)

See more photos & videos

Five Day Trend

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    Extreme
Avalanche Observations
No relevant backcountry observations found for this forecast

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Field Reports
Report Date Observer Snowpack Obs Avalanches Media
View Thu Dec 13 Kreston Rohrig No No Yes (2)
View Wed Dec 12 Eric Deering No No Yes (2)

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Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Steamboat Lake State Park Fri Dec 14 2:00 AM -3 90 1 117 3 -
Crosho Fri Dec 14 1:00 AM 7 - - - - -
Ripple Creek Fri Dec 14 1:00 AM 14 - 0 75 - -
Storm Peak Observatory Fri Dec 14 1:50 AM 13 59 8 251 9 -
Trapper Lake Fri Dec 14 1:00 AM 15 - - - - -
Tower Fri Dec 14 1:00 AM 11 - 4 213 - -
Zirkel Fri Dec 14 1:00 AM 8 - - - - -

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