Bulletin d’avalanche

Mount Shasta

Mount Shasta Avalanche Center
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Danger d’avalanche

Sun
Alpin
3 · Marqué
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

Dangerous avalanche conditions exist above treeline. Continued precipitation and shifting moderate-strong winds have created patchy, and unpredictable wind slab growth at upper elevations of the forecast area. If headed into the backcountry today, pay close attention to the wind direction and snow surface condition. Approach steep slopes cautiously, and if in doubt, stay off of slopes greater than 30 degrees. 

Problèmes avalancheux

  • Wind Slabs

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

    This problem is focused on terrain near and above treeline. Expect to find wind slabs on NW-N-NE-E aspects, with cross loading possible on SE-S-SW-W aspects. With snow levels so high today, wind slab will likely only develop in terrain above 8,000 feet. Previously in a westerly direction, the wind has now shifted to the southwest, turning more southerly this afternoon. Gray Butte has recorded moderate wind speeds all night, with strong-extreme gusts. With pre-existing wind slabs across upper elevation terrain receiving additional wind-blown snow overnight and throughout today, there is some uncertainty about how the snowpack will react. If these slabs fail, they could break large enough to bury or kill you (D2). If in doubt, stay off of slopes greater than 30 degrees near and above treeline.

Avalanche Discussion

Today will be the third considerable day in a row above treeline. With that, it's important to remember why the hazard is elevated, so that its significance isn't lost. For the past three days, wind speeds have been at moderate-strong, combined with a constant stream of rain/snow. For the Mount Shasta area, these conditions can develop wind slabs quick. Recent field observations from the Sun Bowl area, and Ash Creek Butte area have verified the development of dense wind slab over very soft snow (1-finger over 4-finger-fist). Today, as more heavy, wet snow is added to these already loaded areas, slopes may become unglued. Remember, wind can deposit snow five times faster than snow falling from the sky, so it might not take long. As moderate-considerable danger continues, don't let your guard down. When it comes to avalanches, it's a simple recipe, and the ingredients are here.

For lower elevation terrain (below 7,000 feet), rain-on-snow will be the story today. 

Régions couvertes