Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
3 · Marcato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Yesterday's new snow and today's winds will build slabs on the east side of the mountain range that are avalanche prone. You may find the most potential for avalanches in the middle elevation where wind-blown snow has settled. Consolidated slabs and poor subsurface snowpack structure will be the contributing factors in an avalanche today.

Problemi valanghivi

  • Wind Slabs

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

    6 inches of new snow over the last 48 hours and strong ridgetop winds will create slabs of snow around 1 - 2 feet thick in some locations. These drifted slabs could be reactive to human triggering and capable of causing a large and destructive avalanche. Specifically on the steep east facing aspects, of the middle and upper elevations, is where this type of avalanche problem will exist. Use changes in snow hardness and boot penetration, coupled with the directional banners of transported snow, to give you a better judgment of where these slabs reside on the slopes.

  • Persistent Slabs

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

    Faceted snow grains are found in the middle and bottom of our snowpack in much of the lower elevations. This poor snowpack structure has been the catalyst for the prominent collapses and audible whumphing sounds that have been reported recently. Lately, this concerning structure has become relatively stubborn due to warming and rounding of these angular grains, but it has not totally ceased. If you find a consequential steep slope in this elevation zone be cautious when approaching.  

Avalanche Discussion

The strong west and northwest ridgetop winds are our major player today for increasing the avalanche danger to Considerable. Yesterday’s snow totals varied around the forecast zone from: 2.3 inches at Harvard Cabin, 3.1 inches at Gray Knob Cabin, 3.2 inches at the summit, 4 inches in North Conway, 4.5 inches at Bretton Woods, and 5.5 inches at Hermit Lake. The inconsistent nature of the snowfall adds a level of uncertainty to the forecast. 

The recent snow and wind will help load the eastern steep slopes today with newly formed slabs. You will be able to find slabs of different hardness and reactivity as you travel up and across the terrain. Expect wind drifted snow to fail above you and have the destructive potential to bury you or others in your vicinity. Loose dry avalanches were observed yesterday in Left Gully and the Upper Headwall, even later in the afternoon. 

Use your knowledge of poor snowpack structure and newly formed slabs of wind drifted snow to steer you away from the present dangers. Pick a slope that may be wind scoured or lower angle without big consequences below you.

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