Lawinenlagebericht

Northwest Mountains

Crested Butte Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
4 · Gross
Waldgrenze
4 · Gross
Unterhalb
3 · Erheblich
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Kernpunkte

Dangerous avalanche conditions have developed for the NW Mountains and an AVALANCHE WARNING is in effect. Natural avalanche activity is expected to be occurring, and will continue into Tuesday.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1.5–2.5

    Strong winds have combined with the largest snowstorm of the winter, to create fresh soft slabs that are expected to both release naturally, and be reactive to human triggering. These slabs will be largest on the lee sides of ridgelines and cross-loaded terrain features. In more wind-sheltered areas these slabs will be 12 to 18" thick. They have formed on a variety of persistent weak layers, and you can expect unusual avalanche activity. This avalanche problem will be most reactive on west to north to east facing slopes. The cold temperatures and low-density snow, may make conditions feel deceptively soft and not slab-like. If you find these conditions, be mindful that you could convince yourself that the avalanche problem isn't present, and perhaps get caught off guard by a very subtle change. 

    This photo is from December 2020, when we experienced similar avalanche conditions.

Avalanche Discussion

Here are the overnight snow accumulations as of 5am. Irwin area: 14 to 16" snow. Schofield: at 4am: ~17" snow and 1.2 SWE. CBMR Pow Cam: 11". Gothic: Estimated 9" snow and .68 SWE. Upper Taylor: 9" snow and .6 SWE. 

The wind is the other big component of this storm. The Carbonate Hill weather station at 12,600ft, has recorded overnight west-southwest winds averaging 25mph and gusting to 60mph. The CBMR wind station at 11,300ft has recorded southwest winds averaging around 20mph and gusting around 45mph. 

In both the NW and SE Mountain forecasts, natural avalanche activity is expected to have already occurred and will continue occurring on Tuesday. The primary difference in the danger ratings between the two avalanche forecasts is not necessarily avalanche occurrence or likelihood, but the expected avalanche size. The SE mountains will see many small avalanches and a few large avalanches, while the NW Mountains are expected to see many large avalanches. 

We can't stress enough how weak the current snowpack is, that this new snow is accumulating on. Avalanche activity is going to be weird and unusual. Some slopes will have avalanched with only a few inches of new snow, and then those same slopes may avalanche again, as more snow accumulates later in this storm. While other slopes will be able to handle some load before releasing later in the storm, or they will continue to hang in the balance through the week while waiting for the right human trigger. Powder fever is likely in full effect, while the cold and blustery weather will further make decision-making difficult. If you can find enough snow to ride on a slope that was bare ground before this storm, that would be your best way to decrease the threat of triggering an avalanche. The observation tab has good documentation of the old snow coverage going into this storm. 

EVENTS:

  • Avalanche Awareness Night is December 3rd and Beacon Brushup is December 4th.  Details here.

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