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

Tue, Dec 10, 2019 at 7:11 AM
Issued by: Matt Huber

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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Summary

 Dangerous avalanche conditions exist. Avalanches today will be large enough to injure, bury or possibly even kill you. Recent snowfall and strong winds placed a heavy load onto an already weak snowpack, making triggered avalanches likely today. The most dangerous terrain will be near and above treeline that faces northwest through northeast to east and southeast. These slopes are where winds drifted snow into dense, thick slabs that are several feet deep. Avalanches on other aspects and elevations may be smaller, but they will still be large enough to bury you. 

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) 6 to 11 27 to 32 7 to 12
Wind Speed (mph) 10 to 20 8 to 18 8 to 18
Wind Direction W WSW WNW
Sky Cover Mostly Clear Increasing Overcast
Snow (in) 0 0 0 to 1

Archived Forecasts

  • Select Forecast: Valid

Tue, Dec 10, 2019 at 7:59 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 view of our ECTP. There is approx 1 foot of facets at the bottom that ranged up to 2mm in size. (full)
  • The pit was dug at approx 11,400 feet in a gladed east facing area. We had a large collapse when I took off my skies and post-holed through the snowpack. I wonder if this collapsed the near-surface facet later at 44cms, which is why we couldn't produce any results on that interface? The results between the slab and the facets at 31cms was striking, and clearly indicated an instability. (full)

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Five Day Trend

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Avalanche Observations
Report Date # Elevation Aspect Type Trigger SizeR SizeD
View Tue Dec 10 - >TL NE HS N R2 D2
View Tue Dec 10 - TL NE SS U R2 D1.5
View Tue Dec 10 - TL NE SS N R2 D2
View Tue Dec 10 - TL NE SS N R2 D2
View Tue Dec 10 - >TL SE SS N R2 D2
View Tue Dec 10 - >TL NE SS N R3 D2.5

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Field Reports
Report Date Observer Snowpack Obs Avalanches Media
View Tue Dec 10 Matt Huber No Yes (6) Yes (5)
View Tue Dec 10 Sam Feuerborn No No Yes (1)
View Tue Dec 10 Nathan Baier No No Yes (2)
View Mon Dec 9 Matt Huber No Yes (1) Yes (1)
View Sun Dec 8 Matt Huber No No Yes (1)
View Sun Dec 8 Greg Shaffran No No Yes (2)

See All Field Reports

Weather Observations
Station Date Time Temperature Relative Humidity Wind Speed Wind Direction Max Gust 24 Hr Snow
Chapman Tunnel Wed Dec 11 1:00 AM 9 - - - - -
Independence Pass Wed Dec 11 1:00 AM 7 - - - - -
Ivanhoe Wed Dec 11 1:00 AM 12 - - - - -
Sunlight Wed Dec 11 1:00 AM 14 85 9 200 17 -
Schofield Pass Wed Dec 11 1:00 AM 13 - 1 95 - -

See All Weather Observations