Bulletin d’avalanche

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Danger d’avalanche

Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 7 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Dangerous avalanche conditions exist. You could trigger an avalanche large enough to bury or injure a person, especially in upper elevation, wind-loaded terrain.  Cracks shooting from your boards or sled are a sure sign that you’ve found a sensitive slope. 

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2

    Several prominent weak layers exist in our early-season snowpack (read Forecast Discussion below). While this zone received less new snow from Thursday's storm, it was still enough to produce unstable conditions.  While this zone received less new snow, it did get more wind. The resulting wind drifts may be a problem on their own but will be especially dangerous where they sit on top of buried weak layers. 

    Given our weak snowpack, it remains best to stick to lower-angled terrain. Conditions will be most dangerous on upper elevation slopes with evidence of wind drifting. Be alert to signs of unstable snow such as cracking or collapsing—these are obvious indicators you've found dangerous conditions.

Avalanche Discussion

Total snow accumulations vary greatly in the Soldier and Wood River Valley zone following this storm. The Dollarhide area picked up nearly 1.5” of SWE while areas in the southern and eastern portions of the zone were closer to 0.5” SWE. 

Today, moderate to strong NW wind will put weak layers of snow to the test. Here’s a quick rundown of the most prominent problem layers.

September and October Depth Hoar:This layer at the bottom of the snowpack has produced avalanches and obvious signs of instability since Thanksgiving. It's most widespread in upper elevation and middle elevation terrain, but you should assume it's present until proven otherwise.  You can dig quick holes to search for it, and it's easy to identify. Look for loose, sugary snow that appears as a grey layer near the ground.

Thanksgiving Storm Snow: This layer weakened significantly in the cold, clear weather that followed and tall crystals of surface hoar formed in many areas. Crusts developed on sunnier aspects and at lower elevations. This layer (buried on December 7th) was responsible for several small slab avalanches last weekend in the Sawtooths, Smokys and Boulder Mountains. 

To top it off,  the snow surface beneath the current storm snow harbored layers of facets and surface hoar. It's yet to be seen how this layer will react, but we'll certainly know more today. On Wednesday, Ben and I backed off our planned route in the Smiley Creek Drainage of the southern Sawtooths. Remotely triggering a persistent slab avalanche felt like a real possibility, and that was before this storm. Figuring out the relative strength and distribution of these weak layers is complicated, but the take-home point is simple. Our snowpack produced natural and human-triggered avalanches when it was loaded last weekend and today we should expect the same.

Régions couvertes