Lawinenlagebericht

Northwest Mountains

Crested Butte Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

The snowpack struggles to adjust to a week-long loading event.  Natural activity has slowed drastically, but conditions are ripe for human-triggered avalanches like this remotely-triggered avalanche on Mount Baldy yesterday.  You can trigger a dangerous avalanche on all aspects and elevations.  Conservative terrain choices are a must for a safe day in the backcountry.  Expect the unexpected.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–3

    The recent storm formed slabs 3 to 5 feet thick, overloading the widespread facets and faceted crusts that formed during our long December drought and weak layers at the ground.  These avalanches can propagate hundreds of feet wide and have been remotely triggered from thousands of feet away. This is a very challenging problem to manage; give yourself a wide margin for error when traveling near or below avalanche terrain.   The easiest and most reliable way to manage this problem is to ride on slopes consistently less than 30 degrees in steepness.  Other strategies for reducing your risk include riding on recent bed surfaces, but expert assessment skills are required for this.  

Avalanche Discussion

Only a day has passed since the last reported natural avalanches.  The snowpack has just begun adjusting to the new burden placed upon it by a snowy previous week.  Many slopes sit precariously balanced and simply need the added weight of a person to fail catastrophically.  This avalanche, that forecasters remotely triggered, on Mount Baldy exemplifies the tricky position we are in.  Zach and I did not see much for collapsing while riding around during the first half of the day but once we found a shallow spot...whumpf, two dangerous avalanches released.  You can anticipate similar conditions around much of the CBAC forecast area including the Northwest Mountains and snow-favored portions of the Southeast Mountains.  Slabs are thick enough to prevent frequent collapses, but enough variation in slab thickness exists that you can trigger a deadly avalanche on many slopes.  Expect the unexpected.

A Special Avalanche Bulletin has been issued for the Southeast Mountains, where large slab avalanches are especially sensitive to human triggers right now.  This is a product of thinner slabs that are at ideal thickness for human-triggering.  Triggered avalanches remain a threat on the steep hillsides immediately surrounding urban areas at the north end of the valley from CB South to Mount CB.  This sensitive setup can be found at the lowest elevations around Crested Butte and in places like Brush Creek and Cement Creek.  Zach's observation from West Brush Creek points out the booming slope-scale collapses below about 9600 feet.

Tricky times call for conservative decision-making.  Your safest strategy is to avoid slopes steeper than 30 degrees and choose thoughtful routes through the mountains with remote triggering potential at the forefront of your mind.  Some slopes avalanched late in the storm cycle and present a much lower likelihood of having an avalanche problem, however attempting to ride bed surfaces on recently avalanched slopes is challenging to do safely and requires a highly advanced skill set.  Low-angled terrain is riding great right now.

Thursday, a Crested Butte resident was injured by a roof avalanche.   Roof avalanches are most common when temperatures rise above freezing, which we are expecting this weekend.  Be mindful of what's above you and look out for others, particularly children playing in roof sheds. 

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