Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Slab avalanches in wind-drifted new snow are the greatest danger to backcountry travelers. Identify and evaluate features you suspect hold wind drifted snow before committing to steeper terrain. Wet avalanches could be a concern with sun and warming - stay alert to hazards overhead if the day heats up. 

Problemi valanghivi

  • Wind Slabs

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

    Look out for wind slabs on all aspects. New slabs built from 2-4” of snow and wind in the last 24 hours probably exist on both top and cross-loaded slopes in the north half of the compass. Older, more stubborn wind slabs could still be found on southerly aspects. Expect to see more snow and deeper drifts in the alpine. 

    Pay attention to changes in snow texture and depth as you gain elevation and change aspects. Signs of recent wind loading like scoured snow surfaces and drifts behind rocks and trees can point to where wind slabs might try to ambush you. Hand pits and test slopes can help you gauge the bond of wind slabs, but don’t ignore obvious signs of instability like whumps, shooting cracks, or recent avalanches. Use lower angled terrain to navigate around convex rolls and other unsupported features where you are more likely to trigger an avalanche. 

    (4/11/2022)

    Shooting crack in recently formed wind slab near Artist Point (West North). This was a south-facing test slope at 5100'. 

     

Avalanche Discussion

Cold temperatures and unsettled weather continue to prevail across the Cascades. Skies should begin to clear Wednesday morning with periods of sun through the day. Though temperatures and freezing levels are still below normal, the April sun doesn’t need much time to rapidly affect the snow surface. Wet loose avalanches are possible if new snow warms, becomes wet, and weakens on sun-exposed slopes or at low elevations. Minimize travel on and below slopes where you see wet loose avalanches or other signs of instability during sun breaks or with rising temperatures. 

West Central currently sports a wide range of conditions that are better reflected in the forecasts of each adjacent zone near where you travel on Wednesday. To the south Snoqualmie Pass received 2' of snow at pass level with 3' or more at upper elevations. Widespread avalanche activity in the form of storm slab avalanches to D1.5 was reported over the weekend. Less but still significant snowfall was reported from Stevens Pass. Both Snoqualmie and Stevens have seen colder than average temperatures that have turned relatively modest amounts of precipitation into deep new snow. 

West North has gotten consistent snow mixed with periods of clearing and sun that have put down a crust on sun-exposed slopes. The latest batch of snow added 4-8" across that zone with no avalanche activity observed in wind sheltered terrain. Wind speeds indicate another round of wind slabs could be found in this zone and throughout the North Cascades at upper elevations. Prior to this, there was 1' of wind-loaded snow over the melt-freeze crust on leeward slopes with deeper drifts above treeline. Many windward slopes were scoured down to the crust. At lower and mid-elevations, the storm snow from early April has mostly transitioned to a mix of melt-freeze crusts, melt forms, and moist rounded grains.

If you are getting out this week consider submitting an observation here to contribute to the avalanche forecast in the coming days. 

 

 

Regioni coperte