Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

A crust at or near the surface on most slopes will help minimize any avalanche concerns. However, you might still find an isolated lingering pocket of wind-loaded snow that could fail. Watch out for firm pillow-like drifts on unsupported slopes and in rocky terrain.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    At this point, most of the recent wind slabs likely gained strength and healed. However, there have been at least 12 unintentional human-triggered avalanches in the past few days across the WA Cascades. Many of these were very close calls and involved people being caught and carried. While wind slabs are common, this many reported avalanches are not. Two things make these wind slabs unique. 

    1. They exist in strange places and even well below ridgelines. Several E-SE wind events loaded unusual aspects and features. 
    2. Some of these avalanches may have failed on weak facets above the Early February Crust. It may be impossible to tell exactly where this potential weak layer exists and where it’s absent. 

    Be leery of any firm slab in steep terrain. These slides might be more likely in cliffy or rocky areas where the snowpack is often thinner and may be unsupported.

    (2/19/2024)

    This graph shows the general locations of recent natural and human triggered wind slab avalanches since 2/15. 

    Photo: Northwest Avalanche Center

Avalanche Discussion

With the weather stuck in a repetitive cycle, it’s not surprising that the avalanche forecast feels the same day to day. Another round of light showers could bring an inch or so of new snow to the Pass on Tuesday. This time, moderate SW winds could cause it to blow around, but it shouldn’t create much in the way of new avalanche concerns. Similarly, a bit of rain at lower elevations won’t make much difference. It could cause the surface to become wet and sticky, but not really unstable. 

Several travelers on Monday reported a crust on the surface from Sunday’s warmer weather. In some locations, this layer was thicker, in others much less noticeable. It's unclear how high in the terrain it goes, but based on observations, it's likely to at least 4500 or 5000ft. If the sun pokes through in the afternoon, it would need to break down this crust before any wet avalanche concerns could arise. Instead, you may just see a few rollerballs in the inch or so of new snow. 

The upper snowpack consists of various layers of settled snow, crusts, and facets over the prominent Early February Crust (EFC). The exact layers and depths depend on aspect and elevation. In general, about 18 inches of snow exist over the EFC. Snowpack tests this weekend highlighted several potential weak layers, though they were inconsistent. Travelers continue to report “better than expected” conditions. However, breakable crusts, frozen tree bombs, slick surfaces, holes, and open creeks are still quite common.

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