Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Avalanche problems that were created last week have become stubborn and difficult to trigger. Keep your eye out for those lingering thick drifts of snow created by last week's strong winds and consider ways to travel around those features or use travel techniques to your advantage so you don't expose your whole party to the slope at once. A quick-hitting storm will arrive later today that will begin building a new round of wind slabs with the arrival of both increased winds and accumulating snow. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Around mid-day, we'll see winds increasing from the southwest and the west, with the arrival of a quick-hitting storm. By the end of the day, we'll see new snow accumulations in the 3 to 6" range that will add fuel for the new round of wind slabs that will develop through the day. This new avalanche problem will generally be small in size, but we can't completely rule out one of these new wind slabs stepping down into the older generation of wind slabs from last week and producing a large avalanche. 

    If you see the high end of the snow forecast while you are out today, then you may encounter developing storm slabs in more wind-sheltered areas or increased volume for loose snow avalanches. 

     

    An example of a wind slab hanging out below a ridgeline. 

Avalanche Discussion

In general, we are saying out with the old and into the new, as we have moved away from one snowy and windy week, and into a new snowy/windy week. Yesterday's warm temperatures and mild weather was a nice break that allowed last week's new snow avalanche problems to settle out. 

NW Mountains: Concerns for persistent slab avalanches breaking in the upper half of the snowpack have decreased. It's important to understand that we do have a layered upper snowpack with some potential weak layers creeping about. However, you are likely going to need to find an isolated area where the snowpack is abnormally shallow and weak, or a large load to produce an avalanche that breaks into those layers. Today's storm will be interesting to see how it plays out. 3" to 6" of snow in a 4hr to 6hr period will make for some high precipitation rates if we see the upper end of that snow forecast. Combine those potential precipitation rates with elevated winds and, we would see some quickly changing avalanche conditions. If we don't see the upper end of that snow forecast then we may see some changes in the avalanche danger rating for below-treeline elevations tomorrow. The new round of wind slabs that develop today will continue to be in the headlines tomorrow. 

SE Mountains: Persistent slabs are the primary avalanche problem until we get more snow later this coming week. As explained this avalanche problem has been infrequent this month but has still produced some surprising avalanches. The main change has been the addition of below treeline elevations to the problem rose. Those elevations have become weak over the last month with cold temperatures and little accumulating snow. Some parts of the forecast area, received around a foot of snow last week and are developing a new persistent slab avalanche problem. Today's forecasted snow amounts will just barely be enough for a new round of small wind slabs to form.

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