Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Dangerous conditions are expected to persist on Wednesday: Wet loose avalanches could pack a punch, and activity is expected to increase by mid-morning on slopes that receive direct sun. You could still trigger large and surprising avalanches on upper elevation slopes that have been recently loaded by the wind.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2

    Wet snow, warming temperatures, and sun during the daytime is expected to set off another round of loose wet avalanches. This has been the pattern for the past couple of days, and these slides have been packing a punch. Look for wet sticky snow, rollerballs, and fresh fan-shaped avalanches to clue you into this avalanche problem. Avoid large steep slopes, and steer around consequential terrain once you observe these signs. Plan your day to avoid steep slopes that catch the sun, and even be careful of lower elevation slopes in the shade.

    Example wet loose avalanches

    Photo: Matt Primomo

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2

    Strong westerly winds picked up during the tail end of the storm on Tuesday evening and re-distributed lots of snow. The storm also dropped about a foot of new snow at higher elevations. In some areas the new snow is bonding well, but above 5,500ft or so we suspect it may not. Be especially careful on terrain above 6,000ft facing northwest to northeast. This is where old snow is weakest; Where faceted grains rest above a crust from early March. You could trigger slabs up to 2ft deep in wind loaded terrain that run on the crust from early March.

    Look for shooting cracks, signs of wind drifting, and signs of recent avalanche activity. If you find any of these, or if you find weaker snow over a crust beneath the storm snow, don't trust steep slopes. Cornices may be sensitive, so give them some space. Be sure to regroup well away from any steep slope above.

    Example large wind slab avalanche.

    Photo: Alpental Pro Patrol

Avalanche Discussion

Stevens Pass received nearly a foot of new snow above 5,000ft by mid-day on Tuesday. Ski Patrol reported triggering small storm slabs easily first thing in the morning, and a round of wet loose avalanches occurred later. I was able to easily trigger wet loose avalanches on east and south facing slopes below Moonlight by 11am. Slides were running easily and packing a punch. Visibility was somewhat limited on my tour, but I didn't see much natural slab activity. This is not a good thing from a slab avalanche standpoint, because some slopes may still be hanging in the balance awaiting  a trigger (most likely above 6,000ft).

We've been tracking a layer of faceted grains just above a crust from early March, and this recent storm will be the biggest 'load' that it has seen. This is a good time keep your terrain selection reigned in, and plan tours with options for lower angled slopes. Check for soft, weak, sugary snow over a thicker crust. A stout crust formed during the last atmospheric river event on March 1st. The snow that sat around above it became weak and faceted, and were buried on the 8th. You can find this weak layer structure on many shaded slopes. Below 5,500ft the facets have become moist and this layer may not pose an issue moving forward. Above that, the weak snow may persist, especially in alpine terrain.

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