Lawinenlagebericht

Southeast Mountains

Crested Butte Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

Dangerous avalanche conditions will redevelop by this afternoon.  A prolonged heatwave is causing an ongoing cycle of large wet avalanches. Start and finish your tours early while the danger is lower and choose more conservative terrain after surface crusts thaw.  Stay away from steep terrain if you are sinking past your ankles into wet, mushy snow.   

Lawinenprobleme

  • Wet Slabs

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

    Numerous wet slabs released over the weekend caused by meltwater draining into buried weak layers.  Dangerous wet slabs will continue to be a concern until the snowpack refreezes.  Avoid traveling on or below hot, sunbaked slopes, especially later in the day.  The safest time to travel on steep avalanche terrain is early in the morning, and only if the snow surface is frozen solid and supportive under your feet.  You've outstayed your welcome in avalanche terrain if you get off your sled or skis and sink past your ankles into wet snow.  

    4/3: A large wet slab near Ohio Pass

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    In steep, sunbaked terrain, the threat of natural and triggered wet loose avalanches will increase as the snow becomes wet and slushy on all but the shadiest aspects.  In terrain where the snowpack is weak and saturated, wet loose avalanches are gouging deep into the snowpack and entraining dangerous amounts of wet debris.  Avoid traveling on or below steep terrain where you find more than about 6" of wet, mushy snow.  Be especially careful above trees, cliffs, and gullies where even small sluffs can cause harm.  Obvious signs of wet loose avalanches include rollerballs, pinwheels, or if you start sinking deep into a saturated snowpack. Move to colder aspects or lower-angle terrain before the snow gets hot and mushy. 

    4/4: A large, gouging wet loose avalanche on Double Top.

  • Cornices

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2

    This past week, cornice falls have produced a handful of large avalanches. Overhanging masses of snow can break under your feet further back than you might expect, or they can release naturally (ex. Whetstone, Emmons, and Owen). This is a difficult avalanche problem to predict, but cornices are more likely to topple during sustained warmups. Give these overhangs a large berth when traveling near them on ridges, and avoid traveling below large cornices today.

    Recent Cornice Fall on Mt Owen. Photo: Dave Kozlowski

Avalanche Discussion

The heatwave continues, as do the wet avalanche woes.  Since Saturday, we have observed over 40 large wet avalanches (D2 to 2.5 in size).  Our gallery below cherry-picks a few good examples, and our observations page has all the rest.  The most common flavor of wet mess has been large gouging wet loose avalanches. These are occurring because the snowpack is saturated and weak throughout on many slopes.  Once a small surface sluff starts moving, often from a rock band (or from a skier or rider), it can gouge deep into the snowpack.  We've also spotted about a dozen wet slabs that ran over the weekend.  Wet slabs are less predictable and have potential to be larger: they fail as water drains into and compromises the integrity of weak layers.  So far, we've observed wet slabs up to D2.5 in size; there is potential for even larger slides today.  We've seen evidence of both wet loose and wet slab problems on every aspect except due north.  The travel advice for today's wet avalanche concerns is fairly straightforward:  Travel early while the snow surface is frozen and supportive.  With a weak refreeze overnight, this window is quite short or may not exist on some slopes.  After the snow surface starts to thaw, move to a colder aspect or head to mellow terrain.  The snow will start to become unstable only a few hours after sunup on easterly aspects.   You can buy more time by moving to south or west aspects that catch sun progressively later in the day.  As soon as crusts start to soften, or if your terrain of choice didn't refreeze overnight at all, it's time to back away from steep terrain.  

We'll see relief from the intense warming on Tuesday, and the threat of wet avalanches will trend down tomorrow as the snowpack starts to refreeze.  Depending on cloud cover and temperatures, it may take a couple of days before we see a solid, stable refreeze.  

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