Bulletin d’avalanche

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
Voir sur la carte

Danger d’avalanche

Sat
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
Open full map
Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The 4-6 inches of light and soft snow on top of a super stout 9 inch crust made for not terrible riding conditions yesterday. The crust has significant strength and is bridging instabilities that may exist deeper in the snowpack. Lingering winds slabs from the strong winds earlier in the week may exist in isolated locations above treeline. Enjoy the stability and decent weather today and tomorrow before a wintery mix of precipitation moves back into the region early next week.

Problèmes avalancheux

  • Wind Slabs

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

    Strong winds earlier this week from multiple directions created possibility of wind slabs on all aspects above tree line. These have had some time to settle and bond. Although unlikely, unstable wind slabs could continue to exist on top of the crust bed surface in isolated locations. Watch for red flags like shooting cracks and look for poorly bonded wind slabs with hasty pits and shear tests before committing to steep start zones in wind loaded terrain.

  • Loose Dry

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

    The 4-6 inches of light stuff on the surface made for decent riding on low angle, non solar, sheltered terrain yesterday. If you step out into steeper terrain, 35 degrees or greater, be aware that even 6 inches of dry loose sluff can entrain enough snow and momentum to sweep a rider off their feet and carry them into terrain traps or over cliffs. Selecting terrain carefully, riding ridges instead of gullies, and having safe terrain to cut into are ways to mitigate this avalanche problem.

Avalanche Discussion

Last week’s rain penetrated the upper snowpack and then refroze into a robust 9 inch crust able to support the weight of a snowmobile. The crust is bridging instabilities that may exist deeper in the snowpack. 4-6 inches of light cold snow fell on top of the crust: not enough to raise the danger rating significantly, but just enough to make riding conditions decent. Be aware of terrain traps and manage sluff on steep slopes.

Looking ahead: a wintery mix of precipitation with strong winds will be moving back into our area Saturday evening, with the snow level likely above 4000 feet. Heavy wet snow and rain on top of the stout crust will cause increased avalanche danger, so enjoy the stable conditions today and tomorrow; and get a knitting project out for next week.

 

https://youtu.be/AVLDNOXb7N4

Régions couvertes