Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
Voir sur la carte

Danger d’avalanche

Mon
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
Open full map
Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Expect a balmy day with little wind above the inversion. Sun and warm temperatures may soften snow surfaces on steep slopes in direct sun. Small loose wet avalanches may become possible, so consider the potential and consequences before venturing into steeper terrain that faces southeast through southwest. 

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Unseasonably warm temperatures and sun should soften steep slopes that face Southeast through Southwest in the middle of the day. This could make for nice riding if you time it right. These same slopes may become too soft, and create potential for rollerballs, small wet loose avalanches, and other types of snow shed. Things like glide avalanches, and small chunks of cornice could also break off with the warm temperatures. A few signs that slopes are becoming 'over ripe' are rollerballs, and wet punchy snow. If you find yourself sinking  deeply into moist, or manky snow then change aspects or angles.

    Although limited in time of day, and a narrow window of slope aspect, the hazards associated with them are still worth considering. If planning to head into consequential terrain, then weigh the chances with the consequences of getting caught or hit. Slides could be triggered or in some cases might release naturally.

    (12/12/2023)

    Medium sized wet loose avalanches coming off S and SW aspects of Pica Peak.

    Photo: Matt Primomo

Avalanche Discussion

The warm temperatures should peak on Sunday. Winds should be very light or calm at ridgetop, and skies mostly sunny. With all these combined i'd expect snow surfaces on steeper southeast to southwest aspects to become moist or wetted right in the middle of the day. Although its nearly the solistice and the days are short, there might be a time when things feel downright hot on Sunday if you're in south facing terrain. Winds have been in the moderate range for a couple of days and folks have been finding areas of wind stiffened snow. With that said, consider the potential to trigger a wind slab in extreme terrain.

On Saturday, Drew Lovell found minimal avalanche hazard on the north side of Silver Star. Some areas of stiffer wind slab did exist, but were unreactive. Snowpack depths were in the 150-190cm range over the Silver Star Glacier ice, and 120cm at mid elevations. Snow surfaces were mostly sugary dry snow with nice skiing conditions.

The last reported avalanche from the zone occurred overnight of the 12th or early morning on the 13th. It was a small natural wind slab on the north side of Blue Lake Peak, at the top of Liberty Bowl (see photo below). On Thursday, the mountains picked up 1-3" of snow. Observers reported widespread surface hoar on a variety of slopes prior to the light accumulations, and these weak layers are likely buried now.

Near the Cascade crest, you'll find a thin, breakable crust or zipper crust near the surface on many slopes below 6300-6500 ft, that formed from light rain December 10th. Well east of the Cascade crest, the crust is thinner and it's absent in some places near trees. An older crust (12/7) is about  16" below the surface. 

Régions couvertes