Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Slab avalanche concerns have lessened in recent days, but a few slopes could produce a dangerous avalanche.  Terrain with a shallower-than-average snowpack is the most concerning.  Avoid areas that appear rocky, wind-eroded, or previously avalanched; these types of terrain have trigger points where you can impact weak layers.  Favor terrain with uniform and deep snow coverage to reduce your risk of avalanches.  Warm weather and some sunshine may wet surfaces on steep sunbaked slopes; head to cooler aspects if you find more than a few inches of wet snow at the surface.

Avalanche problems

  • Persistent Slabs

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

    In areas with a total snowpack height of over 2 meters, weak layers continue to slowly gain strength. In the NW Mountains, there has been a notable downturn in avalanche activity in March, compared to February. These two recent avalanches were triggered from areas with variable snow depths and highlight the potential size if you find the right trigger point (1 & 2). Since early February the weak layer that produced the most avalanches was a layer of buried surface hoar and small facets, several feet deep on the north half of the compass. There is also potential for avalanches to break on faceted crust layers on some higher, southerly aspects, or depth hoar layers near the ground. Persistent slab avalanches can still be triggered after multiple people have traveled across a slope and will be more likely to be released from a trigger point where the snowpack thins to a below-average depth. Avalanches breaking into old weak layers are unlikely on low elevation, southerly aspects. Slope angles consistently less than 30 degrees away from runout zones are a reliable way to avoid the problem. 

    Remotely triggered avalanche. West, 10,400ft. The snow height here is 115cm. 

    Photo: Evan Ross

  • Loose Wet

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

    As snow surfaces warm, expect the potential for wet avalanche activity to increase.vvSteep slopes with cliffs and rock outcross will produce the most avalanche activity as those rocks absorb more heat and transfer that heat into the snow.  In most cases, this avalanche activity will be small, easy to identify, and avoidable.  Some uncertainty exists about loose avalanches as the temperature climbs a few degrees warmer than Sunday, but cloud-over and southwest winds counteract and possibly keep surfaces cooler.  Keep an eye out for wet avalanche activity today and consider moving to colder aspects as steep and sunny slopes heat up through the day. 

    A recent Wet Loose avalanche from Saturday.  Similar conditions will exist on Sunday.  Avalanche size may increase a small amount as temperatures climb a few degrees warmer.

    Photo: Evan Ross

Avalanche Discussion

The Persistent Slab problem is the primary issue on Monday.  There is a notable difference in the likelihood of triggering a Persistent Slab between the Northwest and Southeast Mountains.  In the Northwest Mountains, the snowpack is commonly 2 meters or deeper.  It is harder to trigger an avalanche with a deep and uniform depth snowpack, but there are places where the snowpack thins, and triggered avalanches become more concerning.  Wind-eroded, rocky terrain, or slopes that previously avalanched this winter will have shallower than normal snowpacks.  The perfect case and point is the avalanche activity from the west side of Mount Baldy on Friday.  Two dangerous avalanches failed in a generally shallow and variable snowpack (1,2) due to wind erosion on westerly aspects.  Take a moment to watch the video in this observation and consider the magnitude and dire consequence of releasing a Persistent Slab.  Steer clear of slopes where you expect to encounter a shallower snowpack and trigger points.  Warming temperatures may slightly increase the risk of natural cornice fall which could act as a trigger for a dangerous slab avalanche.

In the Southeast Mountains, the snowpack is generally shallower with depths commonly less than 2 meters.  A shallower snowpack increases the chance of you impacting weak layers and releasing a deadly avalanche.  Recent avalanche activity points to this increased risk with dangerous remotely triggered avalanches on Double Top, West Brush Creek, and an accident just outside the Southeast Mountains zone near Italian Mountain.  Take a look at this video from Double Top to get a better visual on the increased risk of riding steep terrain in a zone with a shallower snowpack.  On Saturday, a group on Carbon Peak experienced a large collapse in north-facing terrain that "was felt between our group almost 200m apart".  Take a conservative approach to your terrain selection in the Southeast Mountains particularly in areas with less than 2 meters total depth (this is much of the Southeast Mountains).  Don't expect warning signs before releasing a dangerous avalanche and consider the potential of remote-triggering a slope from below.

CBAC Event:  Don't forget the 50th Al Johnson Race is this Saturday, March 17th.  Registration and information can be found at cbavalanchecenter.org.  All proceeds to benefit the CBAC.

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