Bollettino valanghe

Gunnison

Crested Butte Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Hot temperatures and ample sunshine increase the risk of wet avalanches.  Observers noted another round of dangerous natural avalanches on Sunday.  You might find a short window in the morning where the snowpack remains supportive.  The danger will quickly rise as the sun begins to shine and temperatures rise.  You are likely to trigger wet loose avalanches on some slopes and possibly deadly wet slabs.  Once you sink past your ankles, or worse, punch deeply into the snowpack, wet avalanches are a problem.  Get out early while the snow remains supportive and head for low-angle terrain once you encounter a wet, mushy snowpack.  A small chance remains to trigger a dry slab on the highest elevation northerly slopes.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    These avalanches are the most concerning, where you sink deeply into wet snow. In these areas, a small, wet, loose avalanche can gouge through the entire snowpack, becoming powerful and large. In some cases, small wet loose avalanches also trigger bigger wet slab avalanches as they run downslope. Reduce your exposure to this avalanche problem by traveling early in steep terrain before surface crusts thaw. 

    A wet loose avalanche initiating from a thin rocky area in the Happy Chutes on Mt Emmons. 

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    Recent wet slab avalanche activity has most often been triggered by smaller wet loose avalanches releasing higher up on the slope. These avalanches can also be human-triggered. The heavy weight of the wet snow will make skiing out of, or exiting the avalanche, nearly impossible. The most concerning terrain for this avalanche problem is where previously dry snowpacks are transitioning to wet conditions this week—especially in steeper, rockier slopes. Many south-facing slopes have already transitioned to a spring-like snowpack, and high-elevation northerly aspects are unlikely to produce enough meltwater today.  Wet avalanches are less likely early in the day while the snow surface remains frozen and meltwater production is limited. The hazard increases as the snowpack warms and free water moves deeper into the snowpack.

    A pair of fresh wet slab avalanches along Scarp Ridge failed sometime on Sunday.

    Photo: Evan Ross

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–2.5

    Old, hard slabs 2 to 3+ feet thick overlie buried weak layers. This avalanche problem has become isolated in distribution and is difficult to trigger. Without obvious warning signs, avalanches are most likely triggered where the slab is thinner and easier to impact the weak layer below.  Cornice falls can also act as triggers. You can reduce your risk by avoiding steep terrain with a thin or variable snowpack, such as rocky areas, rollovers, or places where wind has created uneven slab thickness. The southern half of the compass and slopes with consistently deep and uniform snow depths offer safer options.

    The last persistent slab avalanche in our forecast area released on Mt Whetstone, around March 11th, during an extreme wind event.

Avalanche Discussion

Clearing skies and increasing temperatures on Tuesday will increase meltwater production.  A few more natural avalanches could release today, similar to the large loose and wet slab avalanches observed on Sunday in this observation.  Avalanches of this size and character would be difficult to survive.  Your best hope for managing the current problem list is to start very early and travel on the snowpack while surface crust remains intact.  You may find this window is exceptionally short.  These two observations (1,2) for the Irwin area highlight the lack of overnight refreeze and the trapdoor conditions you might encounter early in the morning.

Recent wet slab activity has focused on east and west aspects and a few on shadier slopes.  This chart highlights the distribution.  As meltwater production ramps back up, expect similar conditions today and for wet slab conditions to slowly spread towards more northerly terrain (northeast and northwest) at mid and lower elevations.  Assessing the likelihood of a wet slab in the field is incredibly difficult and is best managed by simple avoidance.  Southerly terrain, particularly at mid and lower elevations, has a notably lower risk of wet slabs.

The current weather pattern continues for another week, with temperatures jumping to record levels for the next few days.  Expect the threat of wet avalanches to persist in the coming days.  Eventually, the hazard will subside as temperatures cool and as the snowpack transitions to a more late-spring structure.

It has been a challenging winter.  Little snow, rain events, and now one of the earliest meltouts in memory.  Take a conservative mindset into the mountains today and carefully select terrain.  Temperatures will cool, and snow will likely return before this season is over.  Better conditions and safer opportunities will return.

Regioni coperte