Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

If you are going to take advantage of the sunny and warm weather to explore the mountains on Saturday, keep an eye on the snow surface. If it transitions from “firm and icy” to “wet and sticky”, think about the possibility of wet avalanches on steep slopes. In areas prone to cool east winds, it could take longer for surfaces to soften and reach the threshold for producing avalanches.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Warm and sunny weather will again battle cool easterly winds in an attempt to destabilize the snow surface on Saturday.  Unstable snow could be found in locations where the winds are not as pronounced or later in the day once slopes have had a chance to bake in the sunshine. If you find that the snow surface is soft and moist and you are sinking in past your ankle, then you may want to make your way toward lower angled or shadier terrain. These slides often start at a point, frequently initiating near trees or rocks, can entrain additional snow, and fan out as they descend downhill. You will be more likely to trigger them once the snow is “ripe” on slopes over 35 degrees that see direct sunshine at mid to upper elevations.  

    (2/10/2022)

    Wet Loose debris in an avalanche chute on Granite Mountain. The large slopes above are baking in the sun and funnel their unstable snow into this shady chute. 

    Photo: Public Observation

Avalanche Discussion

We are in the midst of yet another warm spell of weather at Snoqualmie Pass and the snowpack is still in a state of transition in much of the zone. Unlike a few weeks ago when our warmup coincided with a firm rain crust, much of the zone currently contains several inches of settled storm snow atop the Late January Crust. This snow is gaining strength from the top-down as it goes through freeze/thaw cycles but is capable of producing avalanches when the right conditions are met. It could take a few hours for firm morning surfaces to soften and reach the tipping point where you could trigger a slide. You should find variable surfaces based on aspect and elevation, with a mix of ice, breakable crust, and spring-like snow. This could make for some difficult travel conditions, so be prepared with the correct gear and a good travel plan. 

The Late January Crust can be found around a foot below the surface in most locations throughout the zone. The weak snow found at this interface in a “facet-crust sandwich” has not produced any avalanches in our zone to date, but we will continue to watch it throughout this warm-up. We suspect that all avalanche activity should occur in the snow above this easily identifiable layer, where multiple other recent crusts have developed in recent days. During this period, wet avalanches up to size D2 have been observed on sunny slopes by NWAC forecasters, professionals, and recreationalists throughout the zone. Some of the larger slides appear to have been triggered by cornices falling due to the warm temperatures. You should put plenty of space between yourself and cornices or other hanging blocks of snow as you travel.

Regioni coperte