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

Wet snow avalanches are again a threat today which will increase as the day warms. The possibility exists for large, destructive wet-slab type avalanches in isolated areas. These avalanches are most likely on steep slopes that warm the most either by sun or air temperature.  The safest and best skiing will be found on aspects that receive indirect or partial sun where surface wetting is limited to the top inch or two. Track the movement of the sun and be aware that despite the warm temperatures, soft snow will firm up fast after it passes into the shade.  Avalanche danger today is MODERATE.

Icefall is beginning to be a problem and glide cracks are opening up due to warm conditions. Adjust your travel plans accordingly.

Avalanche problems

  • Wet Slabs

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

    This avalanche problem is notoriously unpredictable and highly destructive. Prolonged warming, especially the first warming of a previously dry snowpack creates conditions for this avalanche type. Warm air temperatures and wet snow at the surface are easy to identify red flags. Rain today may increase the likelihood of a wet-slab avalanche, especially if the amount of liquid water exceeds the forecast by adding additional free water into the snowpack. If you find yourself traveling on steep slopes with wet, slushy snow on top, triggering one of these slides will be possible.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1

    Warm air temperatures and some sun will create a sloppy surface layer of wet slushy snow. In snow previously undisturbed by skier traffic, these slides will start at a point and fan out as they travel downhill and entrain additional wet snow. Even if they remain small in size, the risk is that the sloppy surface snow will move underfoot and possibly carry you. Be careful in steep terrain where falls have consequences. Seek out colder snow to avoid this avalanche problem.

Avalanche Discussion

Last night was the third night of barely below freezing temperatures at the highest elevations and the 4th day with air temperatures above freezing at all elevations. Snow is melting during the day, but warm overnight temperatures are preventing the snowpack from refreezing which introduces a large influx of free water into the snowpack setting up conditions for a Wet Slab Avalanche. As melt-water works its way through the snowpack it weakens the snow, particularly in areas with crusts or pre-existing weak layers. This avalanche type is unpredictable because of uncertainty in how vulnerable these weak layers are to the melt water from the snow surface. 

The wet slab avalanche problem today is unlikely (but remains possible) due to two reasons. The first is distribution; despite warm air temperatures, shady aspects are remaining cool at the snow surface which limits snow melt. The second reason is the generally strong snowpack going into this multi-day warm period. This however, does not eliminate the concern for the free-water to take advantage of an ice crust, or even a weaker layer within the snowpack. While unlikely, a large D2 or even D3 in some locations remains possible. 

Looking ahead to the weekend, temperatures below freezing will slow or stop the melting process and allow the snowpack to adjust and stabilize. 

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Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at MWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

Listen to the weekly MWAC Outreach Podcast provided by Ski The Whites. Discussions include snowpack information, weekend outlook, and general avalanche related info. 

Our next free online event is coming up Thursday, March 25 @ 7PM -Opportunity and Cost - with Jake Risch. A Free Zoom Webinar. 

The Harvard Cabin is open for camping only with no entry allowed inside the cabin. There is no access to the breezeway at HoJos.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This forecast is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Avalanche danger may change when actual weather differs from the higher summits forecast.

For more information contact the US Forest Service Snow Rangers, AMC visitor services staff at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or seasonally at the Harvard Cabin (generally December 1 through March 31). The Mount Washington Ski Patrol is also available on spring weekends.

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