Bulletin d’avalanche

Elkhorns

Wallowa Avalanche Center
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Danger d’avalanche

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

Points saillants

A hard freeze overnight at upper elevations has allowed the upper snowpack to harden into a solid melt-freeze crust. Expect hard and supportable snow conditions on all aspects near treeline and above. Below treeline (7500') the refreeze may not have penetrated much below the snow surface and wet loose avalanches remain a concern on steep slopes, especially in the afternoon hours.

Problèmes avalancheux

  • Loose Wet

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

    Lucky for us, we got a solid freeze overnight. Temperatures at 5am this morning above 7500' hovered in the teens. Around 5500' temperatures were in the mid-20's. Below treeline (7500') the refreeze may not have penetrated much below the snow surface and wet loose avalanches remain a concern on steep slopes, especially in the afternoon hours. In areas with a decent amount of tree cover, the snowpack may not have refrozen much at all. Below treeline - avoid and stay out from underneath steep slopes if the snowpack becomes unsupportable. If you see large pinwheels and roller balls coming off steep rocky slopes or sink in above your boot tops when you step off your skis, boards, or sled you should lower your slope angles.

    At upper elevations the cold temps likely penetrated and refroze any moist or wet snow that existed in the upper snowpack. You can expect to find a stout 4-6" melt-freeze crust at the surface on most aspects. The big concern at upper elevations today is losing it on steep icy slopes and tumbling down the hill with not-so-great outcomes.

     

Avalanche Discussion

We can be greatful for the hard freeze last night. Temperatures at 5am this morning above 7500' hovered in the teens. Around 5500' temperatures were in the mid-20's. The freezing temperatures have allowed the snowpack to stabilize on most aspects near and above treeline. Below treeline (7500'), where the temps were not so cold, the refreeze may have only occurred in the upper 6" of the snowpack. As things warm up during the day this slightly refrozen upper snowpack may become unsupportable. If you find yourself bogging down on your sled or sinking in above your boot tops, then this is a good indication of an unstable snowpack and you should avoid and stay out from under steep slopes.

Another concern are the existence of several weak layers deeper down in the snowpack. These warrant your consideration. Yesterday, I was up at 8,000' in the Elkhorns and found a touchy weak layer of preserved graupel down about a foot. The day before, I was up near Hoffer Butte, south of Anthony Lakes, and observed another weak layer down a little over a foot that was reactive in my tests. If you venture into avalanche terrain the next few days, please take the time to dig down at least two feet and look for weak layers or interfaces. While triggering an avalanche on these deeper weaknesses is unlikely, the possibility exists. Avoid likely trigger points in the terrain like convex rolls, rocky outcroppings, and unsupported slopes.

Régions couvertes