Avalanche Advisory for Sunday, April 6, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger today. The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Moderate avalanche danger. Heightened avalanche conditions exist on specific terrain features. Natural avalanches are unlikely and human triggered avalanches are possible.

All other forecast areas of Tuckerman and all of Huntington Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.

AVALANCHE PROBLEM: Wind slab will be forming today in a variety of locations. These are developing due to yesterday’s snow and strong winds, and have the potential to become larger and more hazardous with additional snowfall today. The Sluice, Lip, and Center Bowl are the areas of greatest concern. Forecast areas rated at Low danger today may have unstable snow in isolated areas. These will most likely be found in pockets that are sheltered from strong NW winds today, including many locations in Huntington.

WEATHER: Forget what the calendar says and don’t make decisions based on what the weather is doing in the valley…today will be a blustery winter day in the mountains. The forecast is calling for clouds and upslope snow through the early part of the day. The Observatory is reporting 2″ (5cm) of new snow as of midnight, but how much more will fall during this period of upslope is a question mark that can’t be answered in advance. Although clearing is expected this afternoon, strong NW winds will keep recently fallen snow blowing sideways through the air and temperatures are unlikely to rise above the freezing mark by much, if at all. If you have your sights set on skiing or riding in Tuckerman, I’d recommend rescheduling for another day based on weather and avalanche potential.

SNOWPACK: Beneath any slab that has formed from recent snow, the surfaces currently are quite crusty and firm. This layer and the snow beneath them have good stability, but make for poor conditions for skiing, or for climbing up steep slopes in your ski or snowboard boots. Protected lee areas are the most likely to have new wind slab on top of the crust. Where slabs have formed more than a couple inches deep, you can expect avalanche potential. The depth, size, and how connected it is to adjacent locations should be initial questions in your stability assessments. Expect these new slabs to be growing during the day, and increasing the hazard. The slopes mentioned above as the areas of greatest concern will be sitting solidly in the Moderate range. Other locations such as Left Gully and Hillman’s may have more options for avoiding unstable snow. Also remember that Low danger does not mean no danger. This is not your typical spring day…respect the danger that even a small isolated pocket of unstable slab can pose to you, your friends, and others on the slope below you.

OTHER HAZARDS: Icy, refrozen snow on higher and steeper terrain will limit penetration of boots or skis. Crampons and an ice axe are recommended for travel on steep slopes. Micro-spikes and other creeper style traction devices may be helpful on some lower angle trails, but they do not provide the security of crampons.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory 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.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters.
  • Posted 7:40 a.m. 4-6-2014. A new advisory will be issued tomorrow.

Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2014-04-06 Printable