Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Wet loose avalanches are no April fools joke! You could encounter and trigger small windslabs in alpine terrain, but it's the wet loose avalanches that'll be the problem of the day. Snow could entrain and slide easily on an old crust, so take into account your aspect, time of day, and how moist or sticky the snow becomes.

Lawinenprobleme

  • Loose Wet

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

    Warming temperatures and strong sun that greenhouses through patchy clouds are likely to cause wet loose avalanches on Friday. Expect to find warming snow surfaces by mid-day, first on slopes that face the sun directly and later even low elevation northerly facing slopes may become moist. The snow is resting over a crust, and it may slide fast and entrain easily. Look for rollerballs and moist, sticky snow. Consider avoiding steep areas with increased consequences such as terrain above cliffs, gullies, or complex terrain with large features overhead. 

    Remember to also consider the consequences of other types of wet avalanche problems. Glide cracks have been observed in the Stevens Pass Mountain Resort backcountry, and may continue to open or even fail unexpectedly. 

    Wet loose avalanches could run below treeline on Thursday.

  • Wind Slabs

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

    Winds were strong enough to drift snow, and small ski triggered windslabs were possible on Thursday with localized pockets. If traveling in alpine terrain, expect to find small wind slabs on exposed features. Check for signs of windslab such as stiffer or hollow snow, shooting cracks, and active wind transport. Steer around steeper slopes with cornices or thicker drifts nearby, and be careful of recently drifted areas.

    Example of small wind slab avalanche in wind affected, alpine terrain.

Avalanche Discussion

Dry snow has made a comeback for the time being, and we received about 8" of snow at the pass with slightly less further east in the zone. Josh Hirshberg reported being able to trigger small wind slabs on the firm old crust in very steep terrain. Light snow and some wind drifting was also encountered during the day on Lichtenberg. It appeared to be snowing harder and blowing further east of the pass in the afternoon. Some natural rollerballing was observed on steep SW facing slopes, but in general snow surfaces didn't warm up too much on Thursday. This may set the stage for a fair amount of wet loose activity if the sun does come out stronger on Friday. The temperatures will be a few notches warmer, so we expect this to be the problem du jour. 

A prolonged shed cycle occurred from March 21-29th in the zone. Observers at Stevens Pass noted a small ski triggered wet loose avalanche on Wednesday. On Tuesday, a touring party on the Rock Mountain traverse reported hearing and seeing a few large (D2) natural wet loose avalanches from steep, rocky SE facing terrain above Crescent Lake. Glide cracks have opened on Lichtenberg and on Big Chief Ridge. These may continue to open up and could fail without warning. Cooler temperatures may begin to refreeze the upper snowpack, but you may still find weak, wet snow and potentially still punchy or unsupportable conditions in some areas. 

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