Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

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

You could trigger a large avalanche in wind drifted snow on steep south-facing, east-facing and north-facing slopes. These avalanches could be large enough to bury you. Look for smooth pillows of wind-drifted snow and use strategic route-finding to minimize your exposure to this hazard.

Avalanche problems

  • Wind Slabs

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

    What and where is it: Wind slabs formed from yesterday's snow can be found on steep, south, east, and north aspects above 3000 feet. Some of these could be large and run the full extent of their current avalanche paths.

    How can you recognize it: Look for smooth, rounded, pillows of wind drifted snow compared to wind-textured surfaces. Shooting cracks under your feet or soft snow that is deeper than the top of your boot, are warning signs of the avalanche problem. 

    How can you manage it: Limit time under steep north-facing, east-facing and south-facing slopes above 3000 feet. Look for wind-scoured and wind-textured areas to travel on. Identify warning signs of wind slabs and make conservative terrain choices to reduce your exposure to this hazard.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    What and where is it: A persistent slab problem can be found on steep east and south aspects above 4000 feet (Obs 1, Obs 2). At middle elevations, the distribution of this problem has been found to be isolated to sheltered terrain features, while at upper elevations it’s more prevalent in steep, south-facing and east-facing terrain. These old, hard slabs are up to 1 meter deep and are potentially unreactive; however, if you found a shallow spot in the snowpack or triggered a wind slab on top of these hard slabs, it could step down to the persistent weak layer, causing a very large, consequential avalanche. Note that this avalanche problem exists just to the north of where the Lion Head Trail leads to Split Rock on the summit cone and on the Summer Lion’s Head trail.

    How can you recognize it: Identifying this avalanche problem is difficult without digging a deep pit, as there will be no visible clues. "Whumping" sounds as a warning are unlikely, and the slopes will likely appear unreactive.

    How can you manage it: Understanding where this problem exists in the terrain is the best way to minimize your exposure to the hazard. Plan your travel to avoid these isolated areas of a low-probability but high-consequence avalanche problem.

Avalanche Discussion

The summit of Mount Washington recorded an additional 2.1 inches of snow yesterday, giving a storm total of over 6 inches. This snow has likely produced sizable wind slabs on steep, eastern aspects. With several hours of extreme northwest winds overnight, these slabs may not be as reactive today, however, they may still be sensitive to human triggers. Identify this hazard in the terrain and use strategic route-finding to help reduce your risk to this problem.

The persistent slab problem today is isolated to protected areas at middle elevations, like Summer Lion’s Head trail, but more widespread on south, southeast and east aspects at elevations above 5000 feet. This problem will still be difficult to identify and presents the low probability, high consequence scenario that should be avoided. Without digging down into the snowpack, it won’t be possible to assess the reactivity and potential size of this avalanche problem. Conservative terrain choices should be used to avoid or limit your exposure to this hazard.

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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