Bulletin d’avalanche

Presidential Range

Mount Washington Avalanche Center
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Danger d’avalanche

Tue
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Hard and slick snow surfaces are easy to find in avalanche terrain today. It may be possible to trigger a small avalanche in isolated wind-protected areas where warm temperatures and radiation from the sun are warming areas of wind-drifted snow. Approach larger pockets of soft snow with caution and look out for wet snow, rolling snowballs, and cracking, as signs of increasing hazard.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1

    Small wind slabs resting on an icy melt/freeze crust exist in sheltered areas of lee terrain. Warming of these slabs throughout the day could make them reactive to a human trigger, especially on south-facing slopes, where solar radiation will also be a factor today. These areas are easily identified by smooth, white snow in contrast to the hard, gray, and textured refrozen snow that is widespread across the terrain.

Avalanche Discussion

Small areas of wind slabs were observed yesterday below cliffs, and in sheltered lee areas. This snow behaved stubbornly and was reluctant to transfer energy or propagate on the melt/freeze crust interface. As these same wind slabs are exposed to both warm temperatures and solar radiation today, consider that they may become more reactive to a human trigger. One of the main areas of concern is the pocket of snow below the Sluice water-ice. Though an isolated area of our overall forecast zone, this can see lots of traffic due to the sunny aspect and tendency to hold softer snow. Warning signs for increasing hazard on these slabs today are wet snow and roller balls. 

In some ways, the weather today may be similar to diurnal spring conditions where snow surfaces freeze solid overnight but warm up for good skiing during the day. Something that catches skiers off guard year-after-year is being up high in the terrain after the snow surface refreezes, making for a terrifying and dangerous descent. Remember that if a slope loses access to the sun and its radiation, it will refreeze fast at this time of year. Planning the correct timing for this is tricky and it is important to leave a margin for error. 

Thanks to everyone who has taken time to submit observations of snow and avalanche conditions, both inside and outside our avalanche forecast area. Please keep them coming.

The Lion Head Summer Trail is closed for the season due to avalanche risk. The Lion Head Winter Route is open.

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