Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

An uptick in westerly winds may begin transporting snow on the higher peaks and exposed ridgelines. Along with shallow wind slabs, beware of lingering possibilities to trigger much larger and wider persistent slabs at mid and upper elevations. Look for simpler, less steep, and more supported terrain while these dragons linger.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–2.5

    On many slopes, the snow is still ripe for triggering 2-4ft deep avalanches on a crust. At least a couple of recent large slabs were reported around the Blewett Pass area on Tuesday. A full burial occurred when a skier took a ride and was partially buried in an avalanche on a NW aspect of Jim Hill in the Stevens Pass zone on Tuesday. These avalanches are failing 2-4ft deep, propagating widely, and being remotely triggered from low-angle terrain below or adjacent to steep slopes. You might not receive signs of instability before the whole slope fails. It could be the 2nd, 3rd, or 8th person on the slope that triggers it. 

    Consider avoiding slopes steeper than 30 degrees, and stay well out from underneath slopes of that angle. Give larger terrain features wider safety margins than you normally would. At lower elevations, we don't have enough slab over the weak layer for this to be a consistent problem. 

    (3/6/2024)

    Large slab avalanche off a steep east facing feature in Owl Creek near Blewett Pass.

    Photo: Tony Stewart

  • Wind Slabs

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

    Westerly winds should begin to pick up a little by Thursday morning and drift low density snow into thin slabs. Though shallow, these slabs could be fairly reactive as they'll often build over faceted surfaces. Look for signs of wind slab like observations of blowing snow, textured surfaces, and thicker or hollow sounding areas. Shooting cracks are signs of instability that you may encounter if you find a slab. Identify terrain and features within it where these are likely to exist. Although the consequences of one of these slabs may be minimal, any shallow slab could step down and trigger a much larger, wider avalanche on deeper weak layers. 

    Wind etched surfaces like this are clues that wind slabs may exist nearby.

    Photo: Matt Primomo

Avalanche Discussion

Thursday should be yet another beautiful day in the mountains. A slight uptick in wind may be noticeable on higher peaks and ridgelines. Strengthening March sun is beginning to have more of an affect by the day, and don't be surprised to see a few small loose wet avalanches by the middle of the day. Surface conditions on shaded slopes are mostly still excellent soft, 'recycled powder'. Steeper SE-SW aspects may hold a crust that'll melt down early in the day and might become moist and heavy by afternoon.

A skier triggered a large deep slab on a NW aspect at 6,500ft on Jim Hill on Tuesday. The skier took a ride and was partially buried but luckily ended up with only minor injuries. Our snowpack is complicated due to the intermittent dry spells in February. Besides the early February Crust, there are also potential layers of surface hoar and faceted grains from the 14th, 18th, and 24th. Widely propagating avalanches could fail on any of these layers. Approach the mountains cautiously and enjoy some low-angle powder until these weak layers gain strength. But be patient, as it could be a while before we see improved snow stability. 

This pattern of persistent slab problems can be challenging for backcountry decision-making. It takes conservative terrain management and patience. The structure is especially apparent in the eastern Cascades, where the snowpack is generally more shallow than at the crest. So, if you're venturing into these eastern zones, be prepared to take a step back in your typical terrain selection and understanding of the snowpack.

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