Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

On Sunday, wind slabs could be hidden under a few inches of new snow or exist on various aspects, making them tricky to locate. Instead, identify the features commonly associated with wind-loading and avoid them. Slabs will be more likely above 4500 feet near ridgelines, rocky terrain, or on convex slopes. 

Avalanche problems

  • Wind Slabs

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

    Wind slabs could exist on a variety of aspects on Sunday due to shifting wind directions. In some cases, you could find a wind-loaded pocket on both sides of the same ridge.  Some slabs could be hidden under the surface, so pay attention to changes in the density and depth of the snow as you travel. Firmer or thicker areas are likely wind-loaded and should be avoided. Visual clues such as fresh drifts, cornices, and textured surfaces can give you clues to local wind patterns.  Since the shifting winds and fresh snow may make these slabs challenging to locate, your best bet is to identify common features where wind slabs like to form and avoid them. They'll be more likely near ridgelines, along the base of cliffs, on convex rollovers, and at the tops/sides of chutes.

    In wind-sheltered areas, the low-density snow could produce dry loose avalanches on steep slopes. Don't get tripped up by one of these sluffs and pushed into a terrain trap.

    (3/1/2024)

    A small natural wind slab avalanche on Snow Lake Divide: SE, 4900ft. Note the other picture with a similar slide on the opposite side of the ridge. 

    Photo: Trevor Kostanich

Avalanche Discussion

Preliminary Report: An avalanche accident occurred on Friday, March 1, near Darland Mt in the Ahtanum Meadows area. Two snowmobilers were involved in the slide. One rider was fully buried and killed. The avalanche occurred around 6600ft in a generally east-facing bowl. NWAC staff will visit the accident site on Saturday. Our deepest condolences to the family, friends, and community.

Snow showers and wind speeds should be a notch less on Sunday than on Saturday. But overall, a very similar day is on tap at Snoqualmie Pass - cold temperatures, more low-density snow, shifting winds, and the occasional sun break.

Reports from the Pass indicate that a stark change in conditions occurs as you ascend above ~4500 feet. Below this elevation, up to a foot of recent storm snow sits above a stout crust, resulting in minimal avalanche potential. Above, the crust dissipates, giving way to deep powder and wind-effected features. Not surprisingly, avalanche hazard increases as you cross this threshold. A handful of wind slabs were triggered at these elevations by recreationalists and avalanche professionals throughout the zone on Saturday. Some reports indicate that surfaces warmed quickly during periods of March sunshine - resulting in rollerballs and other avalanche activity. 

While most of these concerns are related to the upper snowpack, it’s worth noting that the majority of our neighboring zones are dealing with a persistent slab problem (East Central, East South, West South, Stevens Pass). In these areas, slides are failing on deeper layers at or just above the Early February Crust (EFC). We do not have any confirmed avalanches on this layer at Snoqualmie Pass. However, as people push further into the mountains, reports of larger avalanches from Wednesday's warmup have started to roll in. You should at least consider the possibility of a very large persistent avalanche if you're heading for big open slopes.

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