Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
1 · Low
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Highlights

Dangerous avalanche conditions will exist today. In steep, north-facing, east-facing, and south-facing terrain above 3000 feet in elevation, large avalanches may occur naturally or be triggered by your weight and be large enough to bury you. Make conservative terrain choices and limit your exposure under steep slopes.

Avalanche problems

  • Wind Slabs

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

    What and where is it:

    New snow and strong northwest wind will build large wind slabs on steep, easterly aspects. These wind slabs could be sensitive to triggers or avalanche naturally. In areas with well-developed avalanche terrain, avalanches could run the full extent of their paths.

    How can you recognize it: 

    Limited visibility may make it difficult to identify new wind slabs in avalanche terrain today. Blowing snow at ridgelines, shooting cracks under your feet or soft snow that is deeper than the top of your boot, are all 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 developing wind slabs and make conservative terrain choices to avoid or reduce your exposure to this hazard.

  • Persistent Slabs

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

    What and where is it:

    Forecasters have identified a persistent slab problem on east and south aspects above 4000 feet (Obs 1, Obs 2). These old, hard slabs are up to 1 meter deep and with the added load of new wind slabs, the potential exists for a smaller avalanche to step down to this 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 there are likely trigger points for this avalanche can be challenging or impossible. Route planning to avoid exposure to this hazard is an effective strategy for this low-probability but high-consequence problem.

Avalanche Discussion

As of 5:30 am, the summit had recorded 3.9 inches and Hermit Lake 7 inches of new snow overnight, giving plenty of snow for transport on the strong northwest winds that will increase throughout the day. With the chance for another 2 inches of snow today, wind slabs could be large, may avalanche naturally and will likely be sensitive to triggers. 

Multiple observations from yesterday (Obs 1, Obs 2) showed new slabs from Sunday night's snow were reactive. Expect to find similar reactive conditions today but with larger wind slabs. Actively take steps to identify areas of concern and use travel techniques to avoid or minimize your exposure to this hazard. 

The persistent slab problem today may be more reactive with the additional load of new snow. This problem 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. If a new wind slab is triggered today, it could have enough energy to affect the deep persistent hard slab below, creating a much larger, much more consequential avalanche. Without digging down into the snowpack, it won’t be possible to assess the reactivity and potential size of this avalanche problem. This is a risk that should be avoided if entering avalanche terrain.

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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