Avalanche forecast

Gunnison

Crested Butte Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Change is slow for the current snowpack state; low likelihood, high consequence avalanches failing near the ground remain a possibility.  Areas with a generally shallower snowpack or specific slopes with variable depths due to rocky terrain or wind effect are the most likely places for you to trigger an avalanche.  Choose slopes wisely by assessing terrain for trigger points and avoid places where you clearly see variable snow depths.  Uniform depths are more commonly found below treeline with near and above treeline terrain offering the greatest variability in snowpack depth.  Additionally, near the surface, you can find fresh, shallow slabs formed from west to north winds over the past two days.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Westerly to north winds and a few inches of fresh snow formed small and easily-triggered wind slabs on Saturday and Sunday.  Be cautious of leeward and cross-loaded terrain features where yesterday's winds blew the snow into thicker drifts.   Look for thicker, denser feeling snow and cracking underfoot to warn you of the problem.   Recent drifts could be dangerous if they carry you into rocks or trees or drag you into a gulley.  You can easily avoid the problem by traveling in wind-sheltered or windward terrain.  

    Forecasters yesterday triggered shallow wind slabs up to 6" thick near treeline. You can find thicker drifts above treeline. Slabs like this could be consequential above terrain traps.

  • Persistent Slabs

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

    The potential to trigger thick slabs breaking on weak layers near the ground should dictate your terrain choices and travel habits.  Avalanches have the potential to break 2 to 6+ feet thick - across entire start zones - evidenced by the hundreds of large avalanches that ran naturally earlier this month.  Avalanches that release from high elevation, leeward aspects will be deep and unsurvivable.   Even in wind-sheltered or windward terrain, you can trigger sizeable slabs that break on weak snow near the ground. The most reliable way to manage this problem is by traveling on slope angles less than 30 degrees that don't connect to steeper terrain above.   If you choose to ride in avalanche terrain, seek out planar or concave slopes with deep, uniform snow coverage, free of shallow spots, rock bands, and variability from winds.  Regroup in safe zones that are clear of unusually wide and long-running avalanches.  

    Most of the avalanches this month have released on weak layers near the ground. The slabs are thick and can propagate surprisingly wide distances across terrain features that might normally feel safe.

Avalanche Discussion

Your avalanche radar should be scanning for two different problems today.  The first, less concerning, and more recent problem, is Wind Slabs at upper elevations.  Saturday morning 1 to 4 inches of snow fell across the forecast area.  Westerly wind on Saturday and more northerly winds on Sunday drifted the new snow into shallow Wind Slabs that may still be sensitive to a person or machine today.  CBAC forecast staff was able to find and trigger a few of these fresh slabs on Saturday on small test slopes.  Wind Slabs pose a threat above terrain traps or on large alpine features where they could be larger in size.  Do not let the surface slabs distract you from the more concerning, and potentially deadly low likelihood/high consequence Persistent Slab problem.

The current Persistent Slab problem requires patience and thoughtful consideration if you wish to recreate in avalanche terrain.  Signs of instability have, more or less, ended and you should not expect collapsing or cracking to alert you to the gremlins in the basement.  Do not allow the lack of overt signs of instability to lull you into complacency with your travel protocols.  Maintain safe up-track routes that protect your group while ascending.  Keep the appropriate spacing between members of your group if you are passing beneath avalanche terrain to guard against a surprisingly wide and deep failing avalanche on upper elevation slopes (for example, moving through an alpine basin with overhead hazard).  For those in the mechanized crowd, consider your regrouping areas while traveling around large slopes to ensure only one person in the group is exposed to an avalanche hazard at any given moment.  Snowmobiles impact the snowpack deeper, or have a large stress bulb, and are more likely to collapse deep weak layers than a skier or snowboarder.  When selecting terrain read the snow surface looking for slopes with shallow or variable looking snow depths to clue you in to the most likely terrain to trigger an avalanche.  Near and above treeline slopes offer the greatest variation due to wind effect and also often have rockier terrain features.  This type of variation in snowpack depth should increase your suspicion for triggering an avalanche and prompt you to pick other terrain options.  Below treeline slopes more commonly have uniform depths with less wind effect.  Regardless of what elevation band you are in, make careful terrain selections that avoid rocky, shallow slopes with variable snowpack depth.  You can also reduce your risk by choosing smaller slopes that have clean runouts which are free from terrain traps to reduce the consequences if you do trigger an avalanche.  Take a look a two recent videos from Zach Guy, one from Saturday in the Northwest Mountains and another from earlier last week in the Southeast Mountains for a visual representation of the problem and explanation.

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