Avalanche Advisory for Friday, February 7, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has MODERATE and LOW avalanche danger. Sluice, Lip, Center Bowl, Left Gully and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully.  All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine has MODERATE avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions exist on specific terrain features.

AVALANCHE PROBLEMSWind slab is the primary hazard today. This wind slab is scattered around the forecast area with the softest slabs being most susceptible to human triggers. These slabs exist primarily in the lee areas which built them Wednesday night. Sluff piles beneath the steepest snow slopes and ice pitches are remarkably light and should be given respect. The reactive wind slab can be skirted in many areas by careful micro-route finding to connect areas of old surface and old, styrofoamy wind slab. Additionally, the potential to trigger the deeper persistent hard slab still exists in some areas. Safe travel and continuous evaluation is the name of the game with this snowpack structure. Higher than forecast windspeeds could push us into the upper end of Moderate.

WEATHER: Blowing snow and summit fog and possibly some scattered snow showers this morning will reduce visibility at times, though visibility should improve in the afternoon. Temperatures are colder than yesterday with summit highs around 0F. Winds from the west at around 45-55 mph may ramp up and potentially begin wind loading start zones again as high pressure builds into the region. 

SNOWPACK: The last storm’s wind slab and avalanche cycle changed some features in our Ravines. Huntington’s northern gullies went into the last storm in a snow starved state and emerged looking much less malnourished. The tops of Damnation and Yale picked up a lot of snow with Lobsterclaw and Right Gully gaining some more snow among the bushes. Avalanche debris has further filled in upper Lunch Rocks and the Fan while widespread sluff piles grew considerably from dry loose avalanche activity. Stability tests and other field work in and around Chute showed poor to good stability depending on slope angle and degree of wind effect with the poorest stability on steep, smooth and soft slabs with firmer slabs of wind sculpted or sluff hammered snow. Thigh deep new snow with a shallow layer of wind slab sitting on 1.5″ of facets turned us around on the shoulder between Left Gully and Chute variation. It is still conceivable that a human triggered avalanche today could step down into the old persistent slab that is scattered around resulting in a larger, and harder, slab pulling out.

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 or the Harvard Cabin. Posted 8:30 a.m. 2-7-2014. A new advisory will be issued tomorrow.

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

2014-02-07 Print friendly