Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
View on map

Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

New snow and wind drifting on multiple weak layers in the snowpack are creating dangerous avalanche conditions.   It will be easy to trigger avalanches in fresh drifts, and some slopes will fail naturally.   Less obvious and less common, there is potential for larger avalanches to break on older weak layers several feet thick.   Instabilities will be smaller and easier to manage on wind-sheltered southerly aspects or smaller terrain features without terrain traps.  The safest riding is on slope angles less than 30 degrees.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Today's new snow will make old layers deeper in the snowpack more susceptible to human and natural triggers than earlier this week.   Persistent slabs up to several feet thick have the potential to fail widely or be remotely triggered from near or below steep slopes.  These dense old slabs may not give warning signs before releasing, but collapsing and cracking are sure signs of danger.   The problem is less concerning on southerly aspects where the recent warmup created thick surface crusts (see video).   The easiest and most reliable way to manage this problem is to ride on slopes consistently less than 30 degrees in steepness.  You are most likely to trigger a persistent slab where the snowpack is shallow or variable in depth, or if you trigger an avalanche in the new snow that gains enough mass to step down.  

    An example of a large persistent slab that ran earlier this week in the Elk Mountains.  The current loading pattern will make avalanches like these more likely to fail.  

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–1.5

    About 6" of new snow and moderate west to northwest winds will form easily triggered and naturally failing soft slabs on leeward terrain features.  Fresh drifts will be most sensitive where they are forming over fragile weak layers on the north half of the compass.  Carefully evaluate slab size and terrain consequences before riding on slopes steeper than about 30 degrees, even in wind-protected terrain.  Cracking or collapsing is a clear sign of unstable snow.  Fresh wind slabs could be remotely triggered because they are forming on surface hoar.   Instabilities in the upper snowpack have the potential to step down and trigger larger and more dangerous persistent slabs where the problems overlap.  

    The new snow is accumulating on weak layers of surface hoar (shown here) and near surface facets on west, north, and east facing slopes, and crusts on southerly slopes.  

Avalanche Discussion

The storm is currently underproducing and looks to fall short of our thresholds for High danger, so the Avalanche Watch was canceled this morning.   As of 5 a.m., storm totals range from 4" to 8" of dense snow, which could double in the Northwest Mountains today.  Today's most obvious and common issue will be fresh storm slabs or wind slabs breaking on surface hoar, near-surface facets, and crusts.  This video describes the storm interface.  You can manage this issue by monitoring storm totals and using small test slopes to gather feedback on how the storm snow is behaving.  We're expecting slabs to be most sensitive in wind-drifted terrain or where you find more than a foot of new snow over surface hoar.  Shooting cracks are a telltale sign that the snowpack is unstable.  

The trickier issue is our persistent slab problem, which won't give easy-to-recognize or reliable feedback today.  Our travel advice is similar to the last week: shallow slopes and slopes with a variable snowpack are most concerning.  However, with new snow adding stress, those old layers will be a little angrier today than they have been all week. Furthermore, there's potential for smaller avalanches in the fresh snow to step down.  We saw that occur on a few slopes earlier this week with wet loose avalanches.   Our problematic drought layers have been productive with every storm and windloading event this winter.  Conservative decision-making and careful snowpack evaluation are essential today.  

Events: Our next Fireside Chat is this Sunday, February 4 at 6 p.m. at High Alpine Brewing Company in Gunnison. A local snowmobiler will talk about his experience with an avalanche burial and rescue while snowmobiling last year.

Regions covered