Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Strong wind overnight into Sunday will again create wind slab hazards on upper elevation slopes and exposed features. Steer around steep slopes near and above treeline, give cornices a wide berth, and stay on the lookout for signs of instability like shooting cracks and fresh slab avalanches. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2

    Strong westerly winds will again create wind slabs on upper elevation slopes and exposed features. You may find areas where the deep storm snow is poorly bonded to recent sun crust or other recent interfaces (See discussion below). Shooting cracks or hollow-sounding snow are signs you could trigger an avalanche on similar slopes. Use small test slopes and hand pits to check for instabilities in the upper snowpack. Avoid wind-loaded, leeward slopes 35 degrees and steeper, and slabs could be deeper and more dangerous at upper elevations. Steer around obvious wind features, thickly loaded areas, and unsupported features such as convex rollers.

    Loose avalanches could still be triggered on very steep slopes. Be sure to pay attention to snow surface conditions as you travel. Rollerballs, and sticky moist snow are signs you could trigger loose wet avalanches. These could be possible in the eastern part of the zone and at lower elevations on Sunday.

Avalanche Discussion

A large (D2.5), fresh slab avalanche was observed on Saturday on Mount Benzarino. It started at around 6,700ft on a steep southeast aspect and was roughly 200ft wide. We don't know what this avalanche ran on, but in nearby zones we've been finding the sun crust from February 25th to be problematic, and responsible for ski triggered avalanches. On Friday, observers noted a very stormy day, with lots of wind drifting snow. Observers had a close call when a natural avalanche dusted them with a powder cloud from the Cutthroat slide paths on Highway 20. On February 22nd, a strong storm created a widespread, natural avalanche cycle up to size D3 in the area. Most of these were above treeline near the base of cliffs, though some may have been in wind-sheltered terrain. One notable slide was 1-2ft deep and propagated 300ft across. It appears that all avalanches ran within the recent snow or at the interface of new and old snow. 

Persistent slab avalanches are unlikely but could not completely impossible. You are most likely to encounter the structure responsible for persistent slab avalanches in the shallower eastern mountains. Check out Drew's observation from Wolf Creek on Friday. Be sure to check out the forecast for the East Central zone if you are traveling to the southern or eastern edge of this zone for more details on the crust/facet persistent weak layer that is problematic there. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regioni coperte