Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

A chance for sun could cause roller balls and small loose wet avalanches at the Cascade crest. You may still be able to trigger large and dangerous avalanches near and above treeline. Put lots of space between where you travel and large avalanche paths.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    You may still be able to trigger dangerous persistent slab avalanches on slopes 35 degrees and steeper. Avoid being on or under large, rocky, unsupported avalanche paths, especially on the north half of the compass. Put a large buffer of terrain between where you travel and large start zones. Minimize your exposure to avalanche terrain and look for safe locations to stop or regroup.

    Indicators of the danger include whumphing collapses, shooting cracks, and tests that propagate or fail suddenly.  If you experience these "red flag" signs, stick to lower angle slopes and avoid avalanche terrain. You can dig down and find the culprit, the late-January weak layer, 1-2 feet below the surface.  In many areas, this layer is a combination of weak sugar-like facets sandwiched between two buried crusts.  The weak layer is deepest near and west of the Cascade crest. In the eastern part of the zone, the weak layer is shallow, sometimes too shallow to produce avalanches. 

    (2/5/2022)

    A skier triggered avalanche near Maple Pass. Three people were caught, one was carried over 400ft with no injuries. E, 6,600ft

    Photo: NWAC public obs

Avalanche Discussion

Expect 2-3" of recent snow near and west of the Cascade crest.  Gusty winds may form very shallow drifts at upper elevations. Similarly, sun on Tuesday could cause some roller balls or very small loose wet avalanches on steep sunny slopes near Washington Pass. To the east little to no snow accumulated. 

On Monday, an NWAC forecaster found variable profile and test results on the late January weak layer. In general, shaded, northerly aspects are still showing the most potential for human triggered avalanches where the crust-facet sandwich is most defined and weakest. On Saturday, professionals reported a recent natural D1.5 avalanche on an east aspect, near treeline on Porcupine Peak (see photo). It occurred in shallow rocky terrain and is suspected to have run on the late January weak layer. Last week, observers noted a cornice fall that triggered a large wind slab avalanche in rocky north-facing terrain. On  February 5th, a notable avalanche was triggered near Maple Pass on an east aspect, near treeline. The slide likely occurred on the late January pwl and involved 3 people, carrying one over 400ft. Widespread whumpfing, rolling collapses, and remote triggering of avalanches were all common last week, though signs of instability have become less frequent in recent days. The recent warm temperatures appear to have helped the late January weak layer gain strength at least on southerly aspects. While there are some signs that the snowpack is gaining strength, tests continue to show sudden results on northerly aspects on the late January crust/persistent weak layer throughout the Highway 20 corridor and at Harts Pass.

Regions covered