Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Wet avalanche concerns persist with ongoing rain. Both small and large wet avalanches remain possible on steep slopes, and natural avalanches may occur. Avoid all steep terrain. If you observe very large, gouging avalanches or widespread natural activity, conditions may be more dangerous than expected—stay out of all avalanche terrain by avoiding or traveling quickly through areas where avalanches run and stop. 

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    As rain continues, we expect lower-likelihood, higher-consequence scenarios, with larger avalanches occurring less frequently.  At Considerable danger, natural avalanches remain possible.

    Avoid all steep slopes, especially near rocks and unsupported rollovers. If you observe numerous fresh avalanches gouging deeply into the snowpack or large wet slabs releasing, conditions are very dangerous. In that case, step back completely and avoid all avalanche terrain, including runout zones.

    Wet loose avalanches began Monday morning as the dry snowpack first became wet. Since then, warm temperatures and 2.5 inches of rain have kept us on alert for continued avalanche activity. We expect wet loose avalanches, wet slab failures that may be several feet deep, cornice failures or random snow chunks breaking off steep rock features. Even small wet avalanches can be powerful enough to knock you off your feet or carry you into hazards.

    (3/2/2022)

    Example photo: Wet slab and wet loose debris above Wellington, similar to what we expect to see on Thursday.

    Photo: Matt Primomo

Avalanche Discussion

I traveled with another forecaster up Skyline on Wednesday morning (observation). We found soggy, wet snow that our skis sank on previously compacted surfaces 6 inches deep on. When I took my ski off, I sunk in up to my hip. Snow was wet or moist as far as we dug, 4+ feet down, and the good news is that there were no crusts with major pooling or water,  We stayed out of avalanche terrain and visibility was poor, yet didn't see many signs of new avalanches. On steep road cuts, we were able to initiate small loose wet slides in the saturated surface snow layer about 10 inches deep.

We expect about 3/4 of an inch of rain Wednesday night and about half an inch on Thursday. Strong winds will ease in the afternoon. This is an atypical setup, with prolonged rain creating significant uncertainty in the forecast. Careful, on-the-ground evaluation is essential if you head into the backcountry. 

There are two crusts in the top 3-4 feet of snow. One is midway through the storm layer, from a warmup on the 12th, and beneath that, the 3/8 crust is at the bottom of the recent storm layer. Plus a thick layer of weak, wet grains sit about 4-5 feet below the surface. These could all be sources of deeper wet avalanches in the coming days. From the 11th to the 14th, there was an impressive cycle of large to very large natural and triggered slab avalanches. By the 15th, avalanches were becoming more difficult to trigger, before wet snow problems began. 

At upper elevations, we have limited information. Older weak layers from February would be difficult to trigger, but they may not have been wetted as much as those at lower elevations. Be ready to assess the upper elevation snowpack if you travel there. Consider the consequences of falling in wet, deep snow. At mid and lower elevations, holes around boulders and creeks may be barely covered and could lead to a dangerous fall. Make sure to keep close tabs on your partners in case you need to rescue them. 

 

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