Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Identify and assess slopes holding wind drifted snow. Small avalanches can have big consequences in terrain with trees, rocks, or cliffs in the runout below. Crusty and wind affected snow surfaces could make traveling through the mountains more difficult than usual.  Avalanche danger is a notch higher in places received more new snow like Mt. Baker and around Baker Lake.

Problemi valanghivi

  • Wind Slabs

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

    Moderate winds at upper elevations could drift any remaining soft snow into thin slabs. Wind slabs should mostly be small and isolated in distribution but easily triggered in locations where they rest over slick crust. Pay attention to changes in snow depth and texture. Use clues like scoured surfaces and cornices to figure out the wind loading pattern in the terrain around you. Pockets of winds slab should have a smooth appearance while the surrounding snow might look roughed up or jagged. Hand shears and test slopes can help you gauge if wind slabs are reactive. 

    (1/15/2024)

    Scoured snow and crust are both visible on this wind exposed terrain feature. Loose snow that was on the surface was blown onto a leeward slope. 

Avalanche Discussion

A firm crust tops the snowpack on sun-exposed slopes. You will probably find some variety of crust on other aspects at low and mid elevations. All kinds of wind affected snow can be found in the alpine. Don’t expect much of a change with high pressure forecast well into next week.

Most of West North picked up an inch or two of new snow on Thursday. The outliers are snotel sites along the north side of Baker Lake that recorded 0.4” of precipitation which would equal about 4” of new snow, with a similar amount observed on the north side of Mt. Baker in Glacier Creek. The amount of soft snow available snow for transport combined with wind speeds are the key metrics for determining the current level of avalanche danger. Find more snow, stronger winds, and signs of transport? If so then avalanche danger is probably more like Moderate where you are in the mountains.

Lingering instability in a layer of weak facets over the Jan 10th crust is still out there, albeit very isolated in distribution. Observers have noted big changes in layering at the crust over short distances. The faceted layer 6-12” down was observed as rounded on most slopes, but preserved and intact on a few others. Isolated whumping was also reported on the 15th. 

You would be most likely to find this problem in terrain that has stayed colder in the last week, especially in the northern and eastern parts of the forecast zone. On the other hand, you are just as likely to find it in shady, wind sheltered terrain as in more exposed areas. Fortunately, the layering in question is close to the snow surface and has been easy to assess with hand shears. If you find big granular snow grains at a clean shear then you probably found the problem as well.

Regioni coperte