Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Shallow Soft slabs of new snow have developed overnight. This generally small avalanche problem will become possible to human trigger on steep slopes, and will be most reactive on northerly facing terrain at mid and upper elevations. Remember, even a small avalanche this time of year could make for an unpleasant ride through rocks, stumps, and all the early season obstacles. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    As of 5am 6 to 9 inches of new snow has accumulated overnight. In many areas, the new snow is accumulating on rough ground or bonding well to the old snow surface. As new snow continues to add up this morning, shallow soft slabs will become possible to human trigger on steep slopes near or above 35 degrees. This avalanche problem may be most reactive on northerly facing slopes where these soft slabs are developing over a lower density and lightly faceted old snow surface. 

    (11/22/2020) Monday 11/23, Early indicator of developing storm instabilities

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    A patchy distribution of hard slabs on top of old, sugary snow exists on some high elevation, northerly-facing terrain features.  Although these persistent slabs are difficult to trigger and relatively small, they would have to power to drag you over rocks, stumps, or early season obstacles.  Be cautious of terrain where you find thick, dense snow overlying a continuous layer of weak, faceted snow on the ground.

    High northerly aspect? ☑. Smooth ground cover? ☑. Weak snow on the ground? ☑. Windloaded slab? ☑. Here's what it looks like when you've found the ingredients for our current persistent slab problem.

Avalanche Discussion

With current snow accumulations, I have low confidence that we'll see much for a widespread Storm Slab Avalanche Problem. Another round of high precipitation rates after sunrise would further develop this avalanche problem. I do expect these new storm slabs to be more reactive on northerly facing slopes and observers reported some early warning signs yesterday from those same areas. 

The new snow is doing little to change the sensitivity of the lingering persistent slabs on some upper elevation northerly facing slopes. If you did trigger one of these harder slabs, it would make for a larger than expected avalanche. Old October snow on the ground is a necessary ingredient for the Persistent Slab Avalanche Problem. This observation is a great tool for understanding where that weak October snow could be hiding out.   

Mark your calendars! December 4th is CBAC's Virtual Avalanche Awareness Night.  A party and educational event, the likes of which you've never seen before.

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