Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 7 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

A prolonged dry period ends today as an approaching storm slowly raises the danger during daylight hours and dramatically overnight.  Today's hazard largely comes from isolated hard drifts that formed during last weekend's wind event, especially on colder aspects.  Avoid previously drifted terrain to reduce your risk.  Carefully monitor new snow totals today, and if you encounter more than 8 inches of new or wind-blown snow, the danger is rising.  Shallow storm snow instabilities could develop if more snow than expected accumulates before sunset. 

Avalanche problems

  • Persistent Slabs

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

    Instabilities involving old slabs breaking on old weak layers are rare due to slab faceting and wind erosion.  There is still a lingering threat of triggering a slab that fails 1.5 to 3 feet deep on depth hoar, facets, and faceted crusts without obvious warning signs.  In the Southeast Mountains, slabs are most likely to be triggered in terrain where slabs are more cohesive from previous windloading. The most reliable way to manage this problem is by choosing slope angles less than 30 degrees.  Wind-eroded and wind-protected terrain offers a safer snowpack where slabs are typically lacking.  

    A secondary issue comes in the form of thin, hard lens-shaped slabs that formed during last week's wind events.  This problem exists at all elevations, though most commonly an issue on the north half of the compass, where it forms over weak facets.  Although they are typically stubborn to trigger now, skirt around these harder drifts in consequential terrain to avoid the threat of getting pushed into trees, rocks, or gullies.    

    A persistent slab avalanche that likely failed during the recent wind event (1/16 to 1/17)

    Photo: Crested Butte Avalanche Center

Avalanche Discussion

An Avalanche Watch is in effect for the Northwest Mountains forecast zone.  If the weather forecast verifies for Friday and Saturday, you can expect dangerous conditions to develop Friday night and High (level 4 of 5) danger to occur on Saturday, with an Avalanche Warning issued.  Be prepared for this dramatic change in conditions.

For Friday, there is some uncertainty about how much the conditions will change during daylight hours.  Most models suggest 3 - 7 inches around the CBAC forecast area, with locations in the Northwest Mountains accumulating the most.  3 - 7 inches is not expected to change conditions notably during daylight hours, but it is close to the volume of snow needed to form new snow avalanche problems.  Since there is some uncertainty about how much snow falls before sunset, the danger rating is shown at the higher level, which you could encounter this afternoon as new snow stacks up. 

The first place you could find a new snow problem is on drifted terrain features at upper elevations.  Although winds remain modest, expect moderate speeds at the highest elevations that can efficiently transport the new snow.  In sheltered terrain, there is a small chance that shallow, soft slabs form and become sensitive in the snow-favored areas.  Additionally, the new snow may add volume to loose avalanches in steep, wind-protected northerly terrain where the snowpack is very weak and faceted.

  

Upcoming Outreach Events:  

Fireside Chat:  Jan 23, Dave Scheefer "Historical avalanches in Gunnison County."  Mallardi Theatre 5-7 pm.

Trailhead Day: Jan 24, Slate River, 10 am-2 pm.

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