Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Recent lowland snow combined with frigid temperatures on Monday demand that you are prepared for winter travel at all elevations. As you ascend in elevation, steer around areas such as the base of cliffs, convex slopes, or confined gullies where avalanches are more likely. At the highest elevations be on the lookout for wind-loaded slopes where larger avalanches could be lurking.

Avalanche problems

  • Wind Slabs

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

    Wind-loaded terrain continues to be the most likely location for you to trigger a large avalanche. Although the winds haven’t been impressive compared to past storms, it doesn’t take much to transport snow this light and fluffy. Several rounds of Wind Slabs likely formed during the storm parade, particularly at upper elevations near ridgelines or at the base of cliffs, sides of gullies, and in rocky chutes. Some of these slabs may be easy to spot while others may be hidden under a few inches of storm snow. Feel for subtle differences in the firmness of the snow as you travel or look for freshly built cornices and big drifts to help identify wind-loaded terrain. Once you identify a slope to be wind-loaded, avoid it by choosing an alternate route.

    (12/19/2021)

    Fresh cornices can help you determine the predominant wind direction and therefore slopes that may be wind-loaded, even if they look smooth.

    Photo: Dallas Glass

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    With storm snow totals hovering around 3 feet, it goes without saying that the sheer volume of snow accumulated over the past few days could be hazardous. We continue to receive reports of shallow and isolated soft slabs, which is why we are categorizing these new snow problems as Storm Slabs. Depending on where you are recreating, Dry Loose avalanches could also be a fit to capture the hazard presented by the recent storm snow. The management of these two issues should remain largely the same, regardless of your categorization preference. You can look at the upper snowpack to see if you are dealing with slabs or loose snow by using upslope tests to look for cracking, or quick hand pits and test slopes to look for failing blocks of snow. These signs would all point toward slab avalanches compared to loose avalanches. No matter which problem you are dealing with, be suspect of slopes over 35 degrees where loose snow could knock you off your feet. These slides could occur naturally if snow is shedding from trees and rocks or could be human triggered.

    (12/19/2021)

    Using simple hand pits while you travel is a quick way to gain some information about slab potential and the depth of potential weak layers in the upper snowpack. 

    Photo: Dallas Glass

Avalanche Discussion

Sunday brought reports from multiple professionals near the crest that conditions are starting to improve as we work our way out of a multi-day storm cycle. In areas north of White Pass not called Rainier, you should find the recent storm snow to be generally right side up and well bonded to the Solstice Crust located about 2 feet below the surface. That said, there have not been any observations from the above treeline band since at least Wednesday, December 22.

Additionally, we do not have any observations from areas south of White Pass and all three of the volcanoes in our zone. Unfortunately, these are the areas that have been hit hardest by the storm cycle. There is some belief that areas further south may be more in-line with conditions at Mt. Hood right now where multiple slab avalanches are being triggered daily. If you are recreating on a volcano or in the southern half of the zone, you could find that the hazard below and near treeline is closer to Considerable.

On Monday, temperatures will be the coldest of the season, so be prepared to dress appropriately. Low elevation snow has accompanied the cold temperatures resulting in some trailheads having more snow or ice than usual. 

Regions covered