Avalanche Advisory for Friday April 25, 2014

This advisory expires at Midnight.  

Tuckerman Ravine has LOW and MODERATE avalanche danger.  The Sluice, Lip, and Center Bowl have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.  All other areas have Low avalanche danger where natural and human triggered avalanches are unlikely. The Little Headwall is an open waterfall and has no rating.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. We are no longer monitoring conditions. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEMWind Slab is the main problem today due to Wednesday night and Thursday snow.  The summit is reporting 7.3″ of snow, melting to 1.27″ of water, in the last 36 hours.  Lower on the mountain, Hermit Lake received much less,  and Pinkham picked up nothing.  Later in the day, if enough solar gain occurs, anticipate the Wind Slab problem to mix in with Wet Loose and potentially Wet Slab problems.

WEATHER: Conditions have changed dramatically in the past 24 hours from socked in clouds, blowing snow, and winds peaking at 106 mph on Thursday to a beautiful morning with dropping winds.  Winds are expected to continue falling from around 50 to close to 20 mph today under mostly sunny skies.  As we move into the evening increasing clouds are expected in prelude to the precipitation forecasted for tonight and the weekend.  Lower on the mountain we will likely get mostly rain, the majority of which should come during the day on Saturday.  In the Ravines and Summit cone you can anticipate rain, freezing rain, sleet and snow. Some verglass glazing is  possible during this event making rocks up high very slick.  From tonight through Sunday morning the current models are predicting 0.6-0.75″ of water to hit our region.

SNOWPACK:  Very high winds on Thursday, exceeding 100 mph (160kph), scoured most areas back to the old hard melt freeze crust peppered with patches of new snow.  As temperatures rise today you may see this old surface move from very hard towards softening.  Expect the large patches of new snow in the areas forecasted at “Low” to have some cold elastic properties early in the day capable of producing a small human triggered avalanche.  A good example is the pocket above the narrows in the Chute. These could send you for a long fall that could be quite bad, but mostly wouldn’t bury you.  Other areas forecasted at Moderate, namely the Sluice through Center Bowl, were in the lee of N and NW winds and picked up more snow.  These area have thicker slabs capable of burying you.  As temperatures rise today, due to a high Spring sun and dropping winds, expect new snow in these areas to warm and initially begin stabilizing.  The big question is whether they heat up long enough to begin losing strength, and hedging towards wet sluffing and wet slab potential.  This is most probable on slopes that are most protected from winds and point directly south such as in the Sluice.  This is something to watch this afternoon.  It is possible these locales will creep up through the Moderate rating, bumping the ceiling of the definition.  Also consider falling ice as a potential trigger.

OTHER HAZARDS:  Icefall hazard will jump forward again as the lead spring hazard today as temperature warm again.  Keep this on your mind, particularly the Sluice ice that looms behind Lunch Rocks.  Ice fall has injured and killed numerous people of over the years as well as triggering avalanches.  Crevasses, that have begun to open up primarily in the Lip area and down towards Lunch Rocks, will likely be hidden by new snow making this hazard very difficult to assess.  The prudent traveler would avoid this areas due both to avalanche problems and crevasses.

Walking from the Bowl to Hermit Lake is the only option as the brook has blown out.  Expect bare spots and bumps on the Sherburne ski trail back to Pinkham.  The lower half of the trail is closed due to melt-out and mud.   Please cross to the hiking trail and walk the short distance to parking lot.

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 845 a.m. 4-25-2014. A new advisory will be issued tomorrow.

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

2014-04-25 Print