Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

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

A major winter storm will come to an end Friday night after several days of heavy precipitation. Give the mountains time to adjust to the massive new snow loads, particularly at mid and upper elevations. Steer around steep open slopes especially where you suspect the wind drifted the snow deeper.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    The reality is we don’t know much about what’s going on at mid and upper elevations in the Snoqualmie area. However, with all the recent snow and the very strong ridgetop winds, we suspect that thick hard wind slabs developed. As the storm clears and winds drop these deeper slabs could sit primed and waiting for a trigger. These may not be the softer wind slabs we often experience here in the Cascades. These could be hard slabs, several feet thick, and capable of growing very large and destructive. Avoid steep slopes below exposed ridges and cornices. Give these fresh wind slabs plenty of space and time to heal. 

    If you see large cornices looming over the slopes above you, look for a different route. Some of these features likely grew large and overhung during the storm. If they fall they could easily trigger the slopes below.

    (12/28/2021)

    Example: This very large avalanche was likely triggered by a cornice fall in steep wind loaded alpine terrain earlier this winter. You could see similar avalanches Satruday.  NE-E aspcet, 5800'. SS-NC-R2-D2.5-U

    Photo: Dallas Glass

  • Storm Slabs

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

    The Pass just got a lot of snow (3-5’ ft since Jan 5) and it’s hard to believe that all that snow has suddenly become stable. Multiple storm snow layers exist from changes in temperature, precipitation rates, and grain type. Simple hand pits and small slopes, may not adequately test these layers due to their impressive depths. Best to give the storm snow a bit more time to gain strength before stepping into larger terrain. This is particularly true above the rain-snow line (~4000’) where the new snow is the deepest. You’re most likely to trigger storm slabs on steeper slopes, near convex rollovers, and at mid-elevations. 

    Below the rain-snow line, smaller shallow storm slabs could still pose a hazard. As temperatures cool, this snow should bond well to the newest crust. However, while we are gaining some confidence in the lower elevation snowpack, the size of the recent storm still sits gives us pause.

    (1/6/2022)

    This 2' deep avalanche occurred on Dodge Ridge near the Summit West ski area Thrusday. Many large and very large avalanches were reported by the DOT. 

    Photo: WSDTO SCR

Avalanche Discussion

While Friday’s avalanche cycles weren’t quite as impressive as Thursday’s, a few notable slides did occur. An avalanche path on Denny Mt ran for the 3rd time in this storm, producing yet another large avalanche. DOT personnel spotted a very large wet debris pile in the Gold Creek drainage on the S side of Alta Mt. Visibility was limited, but the size of the debris was noteworthy. Alpental Ski Patrol and WSDOT reported several paths running multiple times over the past two days, with dry snow avalanches above 4000’ and wet avalanches below.

Snowpack observations have been limited to locations at or near Pass level during the storm. Since the storm began in earnest on Jan 5, more than 38” of snow has been measured. A thin freezing rain crust was reported by multiple professionals Friday. This icy surface sits above a thicker wet snow layer formed by all the rain below about 4000’. Snow return to the Pass around noon, and now several more inches of soft snow sits at the surface. 

Other hazards continue to stay at the forefront of our minds. Glide avalanches could occur at lower elevations even a few days after temperatures cool. Avoid traveling under slopes with crevasse-like cracks. Roof avalanches pose a very real threat along the sides of homes and buildings with heavy snow loads. Snow immersion suffocation (SIS) and treewells mean it’s imperative to keep your partners in sight. With all these hazards and uncertainty, as you step into the mountains, choose trips that allow you to easily manage and retreat from these potential risks.

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