Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Avalanches will become increasingly possible as you rise in elevation today. Watchout for snow in steep terrain at ravine levels deeper than your boot-top that may become wet and unstable from warming temperatures. Above 4500 feet, watch out for drifted areas of dry snow - both can be triggered by a human today.

Problemi valanghivi

  • Wind Slabs

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

    Yesterday's weather conditions, including approximately 5 inches of snowfall, shifting winds, and temperatures below freezing, may have led to the formation of wind slabs above 4500 feet. Be cautious of deeper drifts that may be present on many aspects. These slabs are expected to be dense and may seem stubborn, with few clear warning signs. Before committing to a route, carefully investigate deeper drifts for any weak layers that may indicate instability.

  • Wet Slabs

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

    At elevations between 4000 and 5000 feet, wet slabs avalanches may be possible from rising temperatures today.Yesterday's temperatures, which were near or above freezing at ravine levels, warmed and moistened the recent snowfall. At 3800 feet, the 5 inches of snow was very wet and has likely frozen solid this morning. At this elevation, the recent snow is likely to be homogeneous, without distinct layers, and generally stable. However, as you ascend in elevation, colder temperatures may have limited water penetration last night, potentially preserving some structure in the snowpack that could produce avalanches. With today's warming temperatures and possible sunshine, be aware that these slabs may become less stable. Be aware of rising temperatures and sunshine today working to decrease stability at middle elevations.

Avalanche Discussion

Early this morning, avalanche forecasters encountered challenges in categorizing today's avalanche problem. The recent snowfall may be unstable and able to produce avalanches, whether classified as wind slabs, wet slabs, or warming wind slabs. The primary factor today is elevation; starting at around 4000 feet, the likelihood of encountering snow with the structure necessary for sliding increases as you ascend.

Things to Watch Out For Today: 

  1. Large Wind Slabs: Be cautious of large wind slabs on all aspects. Although the 5 inches of 15% density snow from yesterday may not have been easily transported by the wind, limiting slab size, colder temperatures early in the day, combined with moderate winds and higher snowfall intensity, could have created the potential for large wind slabs.
  2. Rising Temperatures: Increasing temperatures can decrease the stability of the recent snow, particularly at middle elevations. Keep an eye out for wet surface snow as an indicator of decreased stability.
  3. Long Sliding Falls: Conditions for long sliding falls may exist due to refrozen snow on steep terrain. Crampons and an ice axe are essential to prevent a fall.

Looking Ahead: 

The forecast area is currently experiencing a dynamic weather pattern that is set to significantly impact avalanche conditions at middle and higher elevations over the next couple of days. A low-pressure system moving east across Canada, accompanied by its associated frontal boundaries, is set to sweep through the region this weekend. This system will bring a series of weather events, including isolated showers, a warm front followed by a cold front, all contributing to an active and evolving weather scenario. As we anticipate 4–10 inches of new snow accumulation at the higher summits over the next two days, along with increasing winds and blowing snow, the stage is set for a complex and rapidly changing avalanche landscape. The combination of fresh snowfall, wind slab formation, temperature fluctuations, and an exposed icy base creates a challenging environment for avalanche forecasting. In light of these conditions, it is important for backcountry users to stay informed, exercise caution, and make conservative decisions when in avalanche terrain. 

OBSERVATIONS: Please consider submitting an observation of what you are seeing in your travels. Submitting an observation hones your skills, informs other users, and improves our forecasts.

Regioni coperte