• Backcountry Avalanche Forecast
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Tue, Dec 10, 2019 at 7:10 AM
Issued by: Matt Huber

Today

 

Tomorrow

No Rating (-) Watch for signs of instability like recent avalanches, cracking, and audible collapsing. Avoid traveling on or under similar slopes.   No Rating (-) Watch for signs of instability like recent avalanches, cracking, and audible collapsing. Avoid traveling on or under similar slopes.
Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.   Moderate (2) Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully.
  Danger Scale

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Summary

You can trigger an avalanche that is large enough to bury you today.  The most dangerous terrain will be north through northeast to east-facing slopes near treeline. Heavy triggers like snowmobiles will make it easier for you to trigger an avalanche by reaching down to the weak layers near the ground. This is especially true when your track is troughing deep into the snowpack.

No matter what you are on, sleds, ski's snowshoe's etc., approach all steep slopes with caution, giving them a wide margin of safety. You can trigger avalanches from a distance or from below. Shooting cracks and the snowpack collapsing, or whumpfing, as you travel, are signs of an unstable snowpack. Low-angled terrain on slopes less than 30 degrees, without steep terrain above, offer safer options for backcountry travel today.

 

 

 

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.

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 Tue, Dec 10, 2019 at 12:45 PM by Jason Konigsberg Statewide Weather Forecast
  Tuesday Night Wednesday Wednesday Night
Temperature (ºF) 10 to 15 24 to 29 8 to 13
Wind Speed (mph) 8 to 18 5 to 15 5 to 15
Wind Direction WSW WSW W
Sky Cover Partly Cloudy Increasing Overcast
Snow (in) 0 0 0

Archived Forecasts

  • Select Forecast: Valid

Tue, Dec 10, 2019 at 8:02 AM
Issued by: Matt Huber Statewide Weather Forecast  

Snow kept falling yesterday around the Central Mountains, bringing snow totals to well over a foot in many areas. Winds will have plenty of fresh, low-density snow to load onto leeward slopes, stressing a snowpack that proves to be weak already. As the cold front passed, winds shifted to the northwest and built fresh slabs onto many slopes, including southeast- facing slopes. Although it may not stress the buried melt-freeze crusts and facet combinations that linger deeper in the snowpack on these sunnier aspects, these fresh wind-slabs are likely to be tender. 

The continued snow made for some good riding yesterday but visibility was so poor that we have been unable to verify our forecasts with any real confidence. Although given the weak structure, slabs over persistent weak layers, and the continued reports of a collapsing snowpack and shooting cracks, most CAIC forecasters were confident that triggered avalanches remain likely today. The threat of natural avalanche’s is largely over, but not out of the question. As the skies clear and visibility improves, we will be able to assess how widespread the natural cycle was, if at all.

The threat of remotely triggered avalanches remains constant, with new reports coming in almost daily. Approach steep terrain with the assumption that you can trigger an avalanche without being on the slope, and you won’t be surprised when you do.


  • A fracture that initiated in an upper-snowpack weak layer below the cliffs, that stepped to a lower mid-pack weak layer, before gouging down into the old October snow further down the bed surface. 12/6/19 (full)
  • A small avalanche below treeline that illustrates multiple layers of buried Surface Hoar. 12/6/19 (full)
  • Snowpack depth at 10,200 feet on a north-facing slope, 68 centimeters. Extended column tests produced propagating results at the October snow interface ECTP9. 11/30/2019 (full)

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Five Day Trend

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Tomorrow

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Avalanche Observations
No relevant backcountry observations found for this forecast

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Field Reports
Report Date Observer Snowpack Obs Avalanches Media

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Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Mesa Lakes Wed Dec 11 1:00 AM 19 - - - - 1.0
Park Reservoir Wed Dec 11 1:00 AM 6 - - - - -

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