Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
Senza grado
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Winter returns to the forecast area today with new snow and increasing wind. Watch for areas of wind drifted snow this afternoon where you could trigger an avalanche. The deeper the drift, the larger the avalanche.

Problemi valanghivi

  • Wind Slabs

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

    What and where is it:New wind slabs up to 12" thick are most likely on steep, southeast-facing slopes above 3,000 feet, especially in sheltered terrain.

    How can you recognize it: Look for drifts of new snow more than a few inches deep and use a ski pole, hand, or shovel to probe for slab depth and hardness. Blowing snow along ridgelines means slabs are still forming.

    How can you manage it:Make frequent snowpack observations and be cautious on steep slopes with deeper drifts. Informal tests like hand shears should help you to assess size and sensitivity. If you're unsure about the sensitivity or location of wind slabs, consider taking an alternate route in simpler, low angle terrain.

Avalanche Discussion

We’re starting the day with low or no avalanche danger across the forecast area. However, with new snow, dropping temperatures, and wind - avalanche hazards will increase today. Snowfall has already begun, and after several days of warm temperatures we are now seeing a steady drop, setting the stage for wind slab formation by this afternoon.

Forecast models suggest approximately 0.3 inches of water equivalent, which, combined with falling temperatures and increasing northwest winds, should all align to produce new wind slabs on east, southeast, and south-facing aspects above 3,000 feet.  Given the currently warm and wet snow surface, initial snowfall is expected to bond well. However, as winds increase and snow density changes, the most likely failure for any developing slabs will be a mid-storm interface, specifically, softer snow deposited during lighter winds overlain by firmer snow transported under stronger wind speeds later today.

The exact timing of wind slab development will hinge on three primary factors: 

  1. The duration and intensity of the precipitation window.
  2. How quickly temperatures fall to transition fully to snow at middle elevations.
  3. The rate at which northwest winds ramp up to transport the new snow.

Of these, wind is the most predictable, and it will be the driving force behind slab formation.

OBSERVATIONS: Please consider submitting an observation on our website or in the new Avy phone app of what you are seeing in your travels. Submitting an observation hones your skills, informs other users, and improves our forecasts.

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