Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Temperatures are finally cooling but a lot of water fell, much of it as rain even to near treeline elevations, and natural large wet snow avalanches are likely. Avoid traveling on steep slopes, and take extra care to limit time beneath large avalanches paths and gullies even below treeline, since there's a chance large, destructive avalanches could run from above. If you're above treeline, strong wind gusts redistributed the snow that fell, forming thick slabs which we recommend avoiding on steep slopes as it's likely you could trigger an avalanche in these drifts. 

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    You may see a number of wet snow avalanche problems lingering near and below treeline as the intensity of this atmospheric river slows. We are most concerned about wet slab avalanches, as they are very unpredictable and could be deadly. These generally tend to happen naturally and without warning in areas where the rain saturated deeper into the snowpack. If the top foot or more of the snow is wet, steep slopes could slide as a large slab avalanche. Avoid steep slopes in areas where water saturated down into the snowpack. 

    Glide avalanches are also a concern in areas with smooth rock slabs and grassy or low-shrub-covered steep slopes.  You could see glide cracks as hints that snow is slowly shifting downhill and could rip out down to the ground without warning. Avoid traveling beneath glide cracks. With any of these wet snow avalanche concerns, be very aware of terrain up above you, even if you're on a low-angle slope or crossing a gully below treeline. If a large path sitting above you avalanches, it could send heavy, wet, damaging debris down towards you. 

    Wet loose avalanche activity will likely decrease as temperatures cool, but you may still encounter them near treeline where previously dry snow became wet. 

    Wet snow avalanches are still expected to occur on Monday. 

    Photo: Trevor Kostanich

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Much of the storm's precipitation fell as rain below 4000-5000ft, although the final intense burst which arrived Sunday afternoon may have pushed snowlines a little higher. At elevations above the wetted snowpack, you'll still find dry snow which was redistributed with strong winds. Search out signs of wind-affected snow, like shaped features, large pillows, or textured surfaces. Feel for heavier snow. If you find any of these clues, steer around nearby steep slopes.  Use obvious red flags like long shooting cracks or recent avalanches as indicators to avoid steep, wind-loaded slopes as well. 

    Avalanches occurring in wind loaded areas on steep slopes are likely on Monday.  Photo: Dallas Glass

Avalanche Discussion

Natural or human-triggered avalanches could occur below treeline, although they'll likely be smaller. Our main concern at these lower elevations is larger avalanches running from higher elevations. Even if you're on a road or trail where there isn't any snow, if there's steep, snowy slopes up above, there's a small chance an avalanche could still run down a gully and impact the trail or road. 

Cornices have likely weakened with the recent warm temperatures and precipitation. Stay far back from their edges and away from slopes beneath them. 

About 2-3" of water fell throughout the zone since Thursday, and we have reports from neighboring zones of small and large wet snow avalanches which occurred during this event. We expect more occurred during peak warming and precipitation Sunday afternoon and likely into the night, but not many were out to witness it. Residual wet snow problems will remain a problem for the next couple days while the snowpack drains. 

Regions covered