Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Warm temperatures and rain will decrease snow stability on all aspects. Small wet-loose sluff avalanches are possible on steep terrain, and should be easy to predict by watching for wet sloppy snow at the surface. A greater hazard, though less likely, is the possibility for a larger wet avalanche. Minimize your exposure to this hazard by reducing your time in and under avalanche terrain today.

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Rain and water from melting snow will be the primary driver of instability in the snowpack today. Water flowing through, within and beneath existing wind slabs will work to erode and weaken the snow structure. 

    Generally speaking, the older, larger wind slabs found in the terrain were settled and stable prior to today so the chance for a wet slab avalanche may be considered a low probability - high consequence event for many of the more open slopes. However, areas of more unstable snow could be found within the terrain, and these areas will be more likely to fail from the decreased stability from flowing free water.  

    Respect avalanche terrain for the next 24 hours for this low probability high consequence hazard that’s difficult to predict.

    See this observation from Tuckerman Ravine yesterday demonstrating an isolated but potentially unstable area of unstable snow.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Wet loose sluff avalanches are likely to be initiated under your skis in steep terrain today. Watch for decreased surface snow stability as warm temperatures continue. These will be small in size, generally easy to manage, though capable of pulling you off your feet. Consider the consequence of a wet loose sluff induced fall in your travels today.

     

Avalanche Discussion

Rain-on-snow events present challenges to avalanche forecasters. The models we use to determine sensitivity, distribution and likelihood become less effective tools due to the fact that water infiltration is non-linear, meaning water will work itself into and through the snowpack at inconsistent rates.  

New snow last week was followed by a significant melt and refreeze over the weekend, with small amounts of wintry precipitation not resulting in new stability concerns. The upper snowpack is currently stable as a result.

The generally stable snowpack may be able to handle a decrease in stability over the next 24 hours. Or, perhaps not if the water finds a weak layer over an ice crust. 

If the snowpack going into today consisted of recently wind-loaded snow exhibiting the common red flags for instability, it would be easy to predict that rain would tip the scales to slope failure. On the other hand, if we were dealing with a stable, isothermic spring snowpack we could expect the snowpack to drain-out and be less sensitive to rain. Today, we are somewhere in the middle.

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

Please help us and your fellow skiers, riders, and climbers by submitting any pertinent or interesting observations to our website. 

Regions covered