Bollettino valanghe

Northwest Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Dial it back!  Storm totals are approaching 2 feet in the Northwest Mountains.  In steep terrain, it will be easy to trigger avalanches in the new snow and natural avalanches are a serious threat.  Even below treeline, slabs or sluffs will entrain dangerous amounts of snow.  Seek out lower slope angles free from overhead hazards to enjoy the powder safely.  Small terrain features that don't channel into terrain traps offer lower-risk options.  

Problemi valanghivi

  • Storm Slabs

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

    Over 18" of snow since yesterday morning has created widespread instabilities in the new snow.  You will easily trigger soft slabs and loose dry avalanches on slopes steeper than 35 degrees.  Slabs will be thicker and could propagate wider in wind-affected terrain at higher elevations.   At any elevation, instabilities in the new snow will entrain significant amounts of snow and grow to large sizes in long, steep terrain.  Choose low slope angles or small terrain features free of terrain traps to manage the problem.   

    2/14.  A thin slab triggered yesterday at the Anthracites.  The amount of new snow has almost tripled since then.  

Avalanche Discussion

Northwest Mountains:  The Northwest Mountains got walloped by over a foot of snow last night, with 1" per hour rates since yesterday afternoon. Storm totals are now 18" to 24" and will increase more today.  That's a significant load that is expected to create widespread storm instabilities, both soft slabs and sluffs, breaking within the storm snow and at the storm interface.  Observations yesterday indicated that the new snow was not bonding well to the storm interface, which is a mix of crusts, faceted crusts, and near-surface facets. The bottom line is there is a lot of snow that will start moving on you in steep terrain.  Choose conservative terrain.  

Southeast Mountains:  The storm didn't do as well near and east of Crested Butte, with weather stations showing about 3" to 5" of snow overnight, and storm totals up to 10".  The biggest hazard is on wind-drifted slopes, where slabs will be larger and most sensitive.  Winds have evolved from west to south to east throughout the storm, so expect to find drifted slabs on most aspects and in some atypical locations.  In wind-protected terrain, expect to manage sluffing within the new snow, and in a few areas, thin soft slabs.  Conditions are most dangerous at higher elevations or along the boundary of the Northwest Mountains.   We've bumped the likelihood of persistent slabs up to possible today with the concern that the additional loading could make suspect wind-drifted slopes a bit more reactive than earlier this week.  Unusual east winds this morning will be drifting onto slopes with the shallowest and weakest snowpacks which don't often see loading.    

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