Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 7 months ago.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

Highlights

Conservative travel is recommended near and above treeline, where you can trigger a destructive avalanche that breaks up to several feet thick on old, weak layers.  The north half of the compass is most worrisome, or any slope that has seen significant windloading in recent days.  Choose smaller, mellower terrain where poor snowpack structures exist to reduce your risk.  The safest snowpacks are at low elevations and on wind-sheltered southerly aspects.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Potential continues for human and remote-triggered slabs that fail 2 to 4 feet deep on depth hoar, facets, and faceted crusts.  Northerly and easterly facing terrain near and above treeline has been most active this month due to thicker slabs over well-developed weak layers.  Recent northerly winds have expanded activity onto some high, southerly and westerly aspects.   Cracking and collapsing are obvious signs of instability, although your first clear signal could be a dangerous avalanche due to variable and diminishing feedback. The most reliable way to manage this problem is by choosing slopes less than 30 degrees. Wind-protected southerly aspects and elevations below ~10,500' offer lower-risk options, where slabs are less common and weak layers are often capped by stronger crusts. 

    A large persistent slab ran naturally on the west side of Mt. Baldy on Saturday.  

Avalanche Discussion

Now that we’re settled into a mild, dry weather pattern, avalanche danger is on a slow but steady downward trend. Sensitivity continues to decrease, with more slopes proving stubborn to human triggers and fewer slopes reacting easily. The most likely place to find a sensitive snowpack remains on the north half of the compass and where snow depths fall into a “Goldilocks zone” of roughly 70–100 cm. Thicker snowpacks still harbor the problem but often require finding a shallow spot on the slope, while thinner snowpacks frequently lack a cohesive slab altogether. Avalanche activity has been less common and smaller in the shallower Southeast Mountains, making them the first zone to go to Moderate danger. The Northwest Mountains should follow in the next day or two, though larger avalanche potential and a more continuous slab distribution still warrant conservative terrain choices for now.  Remember that this is not an ordinary season - the Gunnison Basin snowpack is at 64% of average. Some of the terrain that is traditionally deeper and more trustworthy by this time of year may be shallower and spookier than normal, whereas some of the terrain that is traditionally spooky this time of year may lack the dangerous slab size and connectivity compared to normal.  As the danger starts trending down, step out into smaller, less consequential terrain first.  As high pressure drags on through most of the month, the doors will open wider, allowing for higher confidence in bigger objectives.

If you’ve been following our forecasts, you likely noticed the recent expansion of the persistent slab rose to include south through west aspects above treeline.   Around the Christmas holidays, those slopes formed faceted crusts and sat relatively thin and wind-eroded through the first week of January.  Over the past several days, steady northerly winds added extra load to some of those previously shallow slopes, introducing the potential for persistent slab avalanches—an issue highlighted by recent avalanches on Hunter Hill (see video) and Mt. Baldy. While this expansion pack is not expected to be as widespread as the problem on north-to-east aspects, it remains something to manage in the near term on recently wind-loaded terrain.

Upcoming Outreach Events:  

Jan 13 Fireside Chat:  Kim Grant from Silverton Mountain at Zuni West Brewing 5-7 pm

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