Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

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

Another round of snow and gusty westerly winds will bring dangerous conditions to middle and upper-elevation terrain where the wind deposits fresh drifts. Stick to wind-sheltered and lower-angle slopes. You may be able to trigger avalanches in wind-sheltered terrain as snowfall intensifies in the afternoon.

Avalanche problems

  • Storm Slabs

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

    You may be able to trigger avalanches in the new snow in wind-sheltered terrain, especially on very steep slopes. You may be able to trigger avalanches more easily in the afternoon as temperatures warm and snowfall intensifies. Use small test slopes to see how the snow reacts before committing to bigger terrain. If you see recent avalanches, cracks, or snow that slides easily, stick to well-supported features and slopes under 35 degrees. 

  • Wind Slabs

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

    Look for westerly winds to actively blow snow and form fresh drifts. This, along with cornices will indicate where you can trigger wind slab avalanches. Recent avalanches or cracks shooting from your equipment are signs to avoid slopes steeper than 35 degrees. Due to the complexity of the conditions, it's best to avoid steep, wind-loaded terrain, especially at upper elevations.

    There have been multiple wind events in the past week, mostly with westerly winds. On Wednesday, however, the wind transported snow from the east. This week, there have been several close calls and a handful of avalanche involvements with wind slab avalanches. Most of these were in neighboring zones, and no injuries have been reported.

Avalanche Discussion

On the 18th, Stevens Pass Patrol reported easily triggered wind slab avalanches, ~6 inches deep, on the leeward sides of ridges and resulting from westerly winds. The biggest avalanche was D1.5. They also reported natural and human-triggered avalanches in the recent snow in neighboring backcountry terrain. Stevens Pass picked up 4-5 inches of snow since the 17th.

We're experiencing a multi-day period of incremental storms, accompanied by periods of strong winds. In the Stevens Pass area, you can find 2.5-3 feet of settled storm snow that has accumulated since March 9th. Recently, NWAC forecasters and other observers have reported reactive wind slabs failing on mid-storm interfaces. Dry and wet loose avalanches have been common on shady and sunny slopes, respectively. In all, over 20 avalanches have been reported in this and surrounding zones, including at least four avalanche involvements.

The snowpack underwent a major transition since the atmospheric river (AR) storm of February 21-25th. This AR crust is now buried over 4ft deep above 5000ft. You'll find a number of crust and old snow layers resting above this crust. On most slopes, the recent snow since the 9th is sitting on a crust from warm temperatures and sun. On high elevation, northerly aspects, there's a chance that you could find weak snow (buried surface hoar or possibly facets) at the March 9th interface, 2.5-3 feet below the surface. On the 10th, observers in the Foss River drainage reported triggering isolated avalanches, which are suspiciously indicative of this weak layer.

If you make it into the backcountry, please share with us what you find by submitting an observation HERE or on the Avy app. 

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