Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Heavy snow, rain and warming temperatures are expected to create dangerous avalanche conditions as the day progresses. Storm slabs could develop quickly near and above treeline, and wet loose avalanches could begin gouging into deeper layers at lower elevations. Stay off of steep slopes if you find more than 8" of new snow, or signs of danger such as shooting cracks or fresh wet avalanches.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Rain on snow is expected to moisten snow surfaces below around 5,000ft during the day. You would most likely trigger these in steep, open terrain. As the day progresses and more rain falls, wet loose slides could begin to gouge down into deeper, old snow layers. Heavier rain may lead to glide avalanches that could occur from rock slabs and grassy slopes.

    If you notice rollerballs and gloppy wet heavy snow, avoid going on or underneath big steep slopes.

    Roof avalanches will continue to pose a threat, so use caution and make sure children and pets stay well out from impact zones.

    (1/8/2022)

    Example loose wet avalanche.

    Photo: Dallas Glass

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Moderate to heavy snow and warming temperatures are expected to create upside-down storm snow. Instabilities may quickly develop during the day as snow accumulates. Slabs could grow to be large towards the end of the day, and with enough new snow could even run naturally. Cornices may become sensitive and could trigger large avalanches below.

    Stay off of steep slopes if you find more than 8" of storm snow or instabilities like shooting cracks. Avoid areas that are actively being loaded by the wind, and avoid cornices. Very large, deep avalanches have recently occurred in the neighboring Snoqualmie and East Central zone. We don't have information about these in the Stevens Pass area, but that's enough information to keep me out of large, high elevation and complex terrain until this atmospheric river winds down.

    Example storm slab from earlier this season.

    Photo: Stephen Semanski

Avalanche Discussion

There is minimal access to most of the zone, and weather stations are down because of the lack of power.  Needless to say, we have very few recent observations. Current snow surfaces before this next storm are unknown, so if you do make it up into the area, be sure to check what the new snow is landing on. Check out this observation from the 8th. Last Friday WSDOT crews reported triggering D3.5 avalanches on the pass with control work, which left debris 60ft high over the road. They observed natural avalanches in the D2.5 size range, some of which had occurred then, and some had occurred on Thursday. On Thursday, they reported multiple avalanches at least D3 in size hitting the closed highway west of the pass. On Highway 2 in Tumwater Canyon, WSDOT reported over 208 debris piles up to 15 feet deep, and several ran into the river. 10 of those slides were very large.

Prior to the storm on the 6-8th, observers noted a couple of buried layers of large, faceted stellars and surface hoar. These layers are probably 3-5ft down at this point, and could be weak layers for slab avalanches.

Regioni coperte