Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Expect increasing potential for Wet Loose avalanches throughout the day as elevated freezing levels and springlike precipitation start to destabilize the snow surface. As temperatures warm, the snow generally likes to sag and fail on steep slopes, cornice lines, or rocky ledges. If you notice the snow is heavy and moist or see new avalanche activity, consider avoiding slopes over 35 degrees. 

Lawinenprobleme

  • Loose Wet

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

    Springtime weather should have you thinking about the possibility of Wet Loose avalanches on Saturday. Rising temperatures throughout the day and the threat of some new precipitation could combine to destabilize the snow surface. Those same weather inputs could help cornices sag and fail or blocks of snow to slide off smooth rock ledges. If you notice that the snow surface has become wet and sticky, take a moment to step off your mode of travel and see how far you are plunging into the snow. If you are sinking in past your ankle, you’ll know the snow has reached the threshold for Wet Loose avalanches. As you travel, look for visual clues such as fresh rollerballs and pinwheels to let you know the snowpack is getting unsettled and these slides are becoming more likely. These avalanches often start at a point and fan out as they descend, entraining snow and growing in size. When the snowpack has reached a point where Wet Loose avalanches are possible, you should steer around open slopes over 35 degrees and give overhead hazards such as cornices plenty of space.

    (3/21/2022)

    Example: Rollerballs and pinwheels are signs of moistening snow surfaces due to warming temperatures, and are a precursor to wet avalanches.

    Photo: Andy Harrington

Avalanche Discussion

On Friday, Alpental Pro Patrol reported a good overnight freeze from the night prior and softening surfaces throughout the day. That makes two nights in a row where a solid freeze helped stabilize the snowpack from the top down and kept avalanche potential muted first thing in the morning. With elevated freezing levels expected on Friday night, you may find that a poorer overnight freeze occurred once you step out of your car on Saturday morning. Despite this fact, we still expect that a crust should exist on the surface in most locations in the morning before daytime warming helps it soften. Wet and generally weak snow should be found on the surface in many locations by day’s end, but the depth of this layer will vary depending on aspect, elevation, and weather inputs. At this time of the year, not even northerly facing slopes will be able to escape the warmth to hold cold dry snow.

The newly forming surface crust should continue to thicken with each freeze/thaw cycle we have over the foreseeable future. Its strength will vary depending on temperatures and liquid input, but generally speaking, it should help to bridge any potential weak layers deeper in the snowpack. This includes the 3/8 facets that are sitting above the Early March Crust around 3 feet below the surface. Although not out of the question, we believe that an avalanche on this layer is unlikely at this point. Any potential slide on these weak grains should need a very large trigger such as a cornice collapse in just the right spot. Elsewhere in the upper snowpack, you should find a mix of large polycrystals, crusts, and rounded grains. We do not have any concerns lower than the Early March Crust at this time.  

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