Bollettino valanghe

Gunnison

Crested Butte Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A good overnight freeze has frozen snow surfaces on the southern half of the compass. A period of good riding will exist as those snow surfaces begin to soften today. Then consider reducing your slope angles to avoid the developing wet avalanche problems as those crusts melt and you sink past your ankles into wet snow. An old persistent slab avalanche problem exists on the northern half of the compass. You can reduce your chance of triggering one of these dry slab avalanches by avoiding slopes with many trigger points where the snowpack thins near rock outcrops for example, or through your slope angle choices. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Weak facets, depth hoar, or collapsible crusts exist on the northern half of the compass and on some sunnier aspects at high elevations.  Slabs on top of these weak layers average 1.5 to 3 feet thick in wind-sheltered terrain. Slabs are thicker and harder in wind-drifted terrain and can step down through older slabs to the ground.    This problem has become stubborn to triggers, often requiring a thin spot on the slope, such as near buried rocks, trees, or where slabs thin from wind effects. Avalanches can break widely across multiple terrain features and be remotely triggered from flat terrain near or below steep slopes without warning signs. The problem can be avoided on slope angles consistently less than about 30 degrees.  

    A couple of persistent slab avalanches that were remotely triggered in the upper Cement Creek area on Friday. 

  • Wet Slabs

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

    As meltwater drains into the snowpack, it can weaken the bonds of buried facets or depth hoar layers and cause natural or triggered wet slabs.  Be cautious of steep, sunbaked slopes as temperatures increase later in the day and the upper snowpack gets saturated.  You can avoid the problem by traveling early in the day while the snow surface is still frozen or by moving to cold, shady aspects.  

    A wet slab that ran on 2/27 on a southwest aspect above treeline. 

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    As the snow surface gets wet and loses cohesion on sun-warmed slopes, watch for natural or triggered point-release avalanches in the upper snowpack.  These can be dangerous if they push you into trees, rocks, or gain volume in long gullies.  Look for rollerballs, pinwheels, or ankle-deep wet snow to identify the problem.  You can avoid the problem by moving to slope angles less than 35 degrees or to colder aspects where the snow surface is frozen.  

    Recent wet loose avalanches on Schuylkill Ridge. S-SW facing terrain. 

Avalanche Discussion

Thankfully, the cloud cover was temporary last night and didn't impact the ability of the snow surface to refreeze. Low temperatures in the valleys dropped down into the teens, while mountain low temperatures dropped into the twenties on average. The thermostat still turns back up today, and once those surface crusts break back down, we'll see wet avalanche problems redevelop. Thankfully, those high temperatures are forecasted to be several degrees cooler than yesterday. 

Since Thursday, February 27th, three wet slab avalanches have been reported. A few more may show up as we continue to get views through the mountains. All of those avalanches have released on steep southerly facing slopes with rock outcrops that help add additional water and heat to the surrounding snow. Loose wet avalanche activity has also occurred on simular terrain. 

The most recent persistent slab avalanche activity in our area comes from these two remotely triggered avalanches in the Upper Cement Creek area on Friday. A more notable avalanche occurred just north of our forecast area in Maroon Creek. Where a very large persistent slab looks to have been triggered by a wet slab avalanche as the two propagated widely through the terrain. You can see that observation here. A similar avalanche event is possible in our area. Otherwise, the persistent slab avalanche problem hasn't seen a loading event since the last wind event ended around February 19th. This has allowed this avalanche problem to continue slowly becoming less reactive, but the existing snowpack structure will not allow this avalanche problem to go away on the north half of the compass any time soon. 

As we look ahead to the coming week, we will finally see a return to winter-like conditions. Wet avalanche concerns will be erased as snow surfaces remain frozen, and we can turn our attention to new avalanche problems developing as enough snow accumulates. 

Regioni coperte