Bulletin d’avalanche

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Continued snowfall today will create heighten avalanche conditions in specific areas. Storm totals may not be impressive but are enough to build cohesive slabs. Human triggered avalanches are possible on steep planar or convex slopes.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Recent snowfall and today's current storm are enough to build cohesive slabs in the recent storm snow. The main avalanche problem is new snow sitting on top of last weekend's varied surfaces of old snow, crusts and possibly intermittent surface hoar. While southerly winds have been light, ridgetop winds on Sunday may have transported enough snow onto northerly slopes to build isolated areas of packed wind slabs. Signs of previous wind slab will be covered over and difficult to assess today. Keep this, and the above, in mind while route planning.

Avalanche Discussion

The snowpack has changed a lot in the last 2 weeks. Total snowpack heights in the middle and upper mountain elevations nearly doubled in some locations. From late February to early March the Silver Valley zone received up to 5.1 inches of snow water equivalent (SWE) and strong South winds. This large amount of storm snow is gaining strength and stability. In the middle and upper mountain elevations, this storm snow is currently consolidating to about  3 - 4 feet of snow on top of an early February rain crust.   

Low elevations have seen warm temperatures and notably lower snowfall totals. Moving up in elevation, the current avalanche problem and snowpack instabilities are mainly within the top one foot of new snow that has fallen over the last few days. Higher density snow Sunday (3/10) and today's storm snow has fallen on a variety of surfaces -  thin melt freeze/sun crust, previous wind slabs, and possibly intermittent surface hoar from Saturday 3/9. Continued snowfall will slowly heighten avalanche conditions today. Build a margin of safety by carerfuly evaluating steep planer slopes, convex rollovers and start zones likley to harbor wind slabs. If preserved, buried surface hoar will likely be found in wind and solar sheltered openings. Think critically, be observant, set decision making plans and later reflect. 

Please consider submitting an Observation with any information about the conditions you find. These help us build a more complete picture of what is going on in the snowpack across the forecast zone. Thank you.

Régions couvertes