Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

Tue
Alpine
1 · Low
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

You could trigger an avalanche on very steep terrain above 3000 feet that faces east or south. Rain and mixed precipitation will add weight and stress onto a snowpack that sits on top of a slick crust in many areas. Rain-on-snow events can be highly unpredictable. Giving avalanche terrain time to settle and refreeze is a smart move today.

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    What and where is it: Mixed precipitation and rain is expected to fall at all elevations today, which will add weight and stress to old wind slabs. In many areas, these old slabs do not exist, but in specific areas on east and south-facing slopes where slabs are 1 - 2 feet thick, liquid water could have the chance to penetrate the snowpack and increase the chances of triggering a wet slab avalanche.How can you recognize it: Watch out for mixed precipitation changing over to rain. Rain and warming would contribute to a more unstable snowpack. Assess the amount of rainfall on previously dry snow and dig into the snow to see how far down rain has penetrated the snowpack. How can you manage it: Remember that rain-on-snow events can be highly unpredictable. Additional uncertainty comes from the timing of the changeover from mixed precipitation to rain and how much liquid water is available to enter the snowpack at different elevations. Give avalanche terrain a wide-margin for error today by considering any large, developed snow slopes that are above you or around you.

Avalanche Discussion

Expect messy, wet weather conditions today with avalanche concerns that are highly dependent on how much liquid rain falls at various elevations. Middle elevations between 3000 and 5000 feet have the most well-developed avalanche problem, consisting of old wind slabs that have been largely unreactive but are sitting on top of an old rain crust from December 19th. Where these thicker old slabs exist, there is a potential to trigger an avalanche, especially if water is able to make its way onto the buried rain crust and lubricate that surface. This could happen from water penetrating directly through the old snow, or from water falling onto the old rain crust where it is exposed and draining down into areas where old slabs exist. At upper elevations, it is more likely that there will be a shorter window of liquid rain and more accumulation of sleet and ice, which may encase the snowpack in many areas. Tonight, expect temperatures to fall rapidly below zero, refreezing a wet snowpack. Additionally, as mixed precipitation changes over to snow, watch for the potential of small new wind slabs that begin to develop in terrain that is highly protected from the wind. While it is unlikely to find a significant new wind slab problem tonight, this is dependent on the timing of falling temperatures at various elevations. If temperatures drop earlier, there is a chance for up to 3 inches of new snow which will be getting redistributed by high winds. With so much uncertainty around precipitation types at various elevations, and the unpredictable nature of rain-on-snow events, letting the snowpack settle down and refreeze is probably a smart move today. 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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