Avalanche forecast

West Slopes South

Northwest Avalanche Center
View on map

Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Chilly east winds combined with plenty of cold dry snow already in place is a good recipe for Wind Slab development on Saturday. Visual clues such as actively blowing snow should help you to identify unstable pockets to steer around. These slabs may form in some uncommon areas due to the atypical wind direction, possibly threatening your typical travel routes.

Avalanche problems

  • Wind Slabs

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

    Winds should intensify and shift easterly over the weekend. Look for Wind Slabs to develop near ridgelines, convex rollovers, or rocky features such as confined gullies. Easterly winds often create slabs on different aspects than you may be used to or could cross-load slopes and gullies. So keep your observation eyes open and don’t immediately default to your usual travel patterns. Look for actively blowing snow, newly built sharp cornices, wind-stiffened snow, or visual clues like fresh drifts behind objects to help key you into wind-loaded features to avoid. 

    Where they have developed, cornices are likely still young and fresh at this point in the season. Be cautious traveling on or below these ticking time bombs, they notoriously break in unpredictable ways.

    (12/1/2022) Rime and wind drifts can help you anticipate wind loaded slopes. Photo: Dallas Glass

Avalanche Discussion

It’s been quite the stormy week for the West South! The storm totals are in and most mountain locations around the zone received 30-40 inches of new snow since last weekend. At lower elevations, the snowpack has more than doubled since Tuesday. A few dribs and drabs could squeeze out another inch or two by Saturday morning, but generally speaking, we’ll get a break from the snowy weather. That doesn’t mean it won’t be winter-like in the mountains. The cool east winds should strengthen and keep the thermometer on the chillier side.

All of this week's snow fell on an early-season snowpack and a natural slab avalanche cycle was reported to have occurred in all elevation bands during the height of the storm. On Thursday, Crystal Mountain Pro Patrol triggered 3 large avalanches using explosives that failed on older snow layers (likely the 11/22 interface). These slides all occurred in upper elevation, wind-loaded terrain with a northerly tilt to the aspect. Although the lower snowpack around the West South is thought to be generally strong, these avalanches remind us that early-season snowpacks are notoriously variable and can be unpredictable. Be cautious and do your homework before stepping into terrain. We are all still collecting data about conditions and potential weak snow. You can help us and the community out with this by submitting public observations.

Speaking of doing homework, if you are traveling on a volcano, even less information is known at this time. Access and observations from areas such as Paradise, Mount St. Helens, or Mt. Adams have been limited. Automated weather station data indicates that these areas likely received close to 3 feet of new snow this past week and could have more pronounced wind-effect. 

What we do know is that even a small slide could hurt you in high-consequence terrain. And right now there may be more consequential terrain than normal. Even with the increase in snow depth, open creeks, holes around rocks, and plenty of small trees exist to make travel more difficult and dangerous than you may be used to. Take it slow and keep your partner in sight with all these early-season and deep snow hazards.

Regions covered