Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Increasing wind and rising snowlines throughout the day will increase the avalanche danger as the day continues. Newly formed wind drifts will build and become more sensitive, so identify wind textured or heavier snow and steer around those locations on steep slopes. Rain will shift higher as the day progresses, and small wet avalanches could occur. 

Problemi valanghivi

  • Wind Slabs

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

    Wednesday will feel very different from Tuesday. Strong east/southeast winds and over 6 inches of snow falling during the day will redistribute snow into thick slabs in unusual locations, possibly further downslope and on different aspects than you're used to. Danger will increase as you gain elevation into more wind-exposed slopes, and beware that places you traveled earlier without slabs could have developed reactive slabs later on. 

    Identify actively drifting snow, and avoid those areas on steep slopes. Drifts tend to form on the leeward side of ridges, around features, and in gullies. Search for "red-flag" signs of instability, such as recent avalanches, blowing snow, and cracks shooting through the snow. Steer around cornices and wind-loaded pillows on steep slopes.

    Example photo: Wind tends to deposit snow around rocky outcroppings and other features that break up a smooth, level snow surface. Avalanches are easier to trigger in these areas. 

  • Loose Wet

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

    Rain will slowly creep up the mountains, into the mid-elevation band. Forecasts vary, but we expect to get wet loose avalanche activity at lower elevations, possibly at mid-elevations too. Avalanches should remain in wet surface layers, but there's a chance a wet loose avalanche could trigger a larger slab avalanche as well. 

    Monitor what's coming out of the sky- is it snow or rain? If the snow surrounding you gets wet and sticky, or you notice small rollerballs running down steep slopes, shift away from steep features and move to low-angle terrain away from steep slopes. Wet avalanche initiation is most common near rocks, or quite possibly from tree bombs falling out of trees, which you can expect an abundance of on Wednesday. 

    Example photo: Rollerballs initiating from trees and other steep, rocky areas. These are indicators that more wet avalanche activity could follow. 

Avalanche Discussion

We had a lull in the steady stream of storms on Tuesday, and several people were out in the Baker backcountry, as well as sledding at Canyon Creek. The previous day's forecast of Considerable trending to Moderate appeared to play out. Cracking was identified in some areas, but not others, on wind slabs. A few residual storm instabilities still exist in the top foot or so of snow, that was found to be reactive in some spots and not others. 

Snow depths vary across the zone. At 4800 ft, I found 6.5 ft of snow at Heather Meadows on Monday, with the 12/18 crust 3 ft down, and about 4.5 ft of snow in Canyon Creek on Tuesday, where the crust was just over 2 ft deep. Both pits showed a generally favorable structure, with lighter snow over progressively harder layers and good bonding to the crust. Minor storm instabilities existed in the top foot, but they did not propagate in extended column tests.

State and local resources are working diligently to reduce the impacts of destructive storms that occurred earlier this month. We can help by respecting affected communities, complying with road closures, and adhering to ski area uphill travel policies.

Regioni coperte