Avalanche Advisory for Monday, February 9, 2015

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. The only exceptions to this rating are the Lower Snowfields which is Moderate and Little Headwall which has Low avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible in Lower Snowfields. Natural and human-triggered avalanches are unlikely in Little Headwall.

Huntington Ravine has Considerable avalanche danger.  Dangerous avalanche conditions exist. Natural avalanches are possible and human triggered avalanches are likely. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential.

AVALANCHE PROBLEM: Continued snowfall today will contribute to the wind slab and dry loose avalanche problems today. The 6” (15cm) of low density snow that fell yesterday coupled with 1-3” (2.5-7.5cm) more today will build easily triggered slabs in steep, leeward terrain. Drifting and sluffing were observed yesterday so be vigilant of piles of sluff debris forming slabs beneath steep pitches of ice and rock. Though not as destructive as the more typical hard wind slabs, today’s avalanche problems could still pack a punch and contain enough snow to bury a person, so choose your terrain very carefully. Watch for slabs building in lee features of SSE winds as well as the westerly wind yesterday morning and Saturday night.

WEATHER: Light snow continues today with 1-3” (2.5-7.5cm) forecast through the day and a trace to 2” (TR-5cm) overnight. Warm air aloft may produce riming conditions again today. SW winds will be light again in the 15-30mph (25-50km/h) range on the summit with moderating temperatures near 10F (-12C).

SNOWPACK: The summit recorded 5.7” of 7% density snow yesterday from midnight to midnight. 6.3” (16cm) of 7% snow was measured on the 24 hour collection board at Hermit Lake at 0630 am. Much of the snow appeared to be even lighter than the 7% average consisting of well-developed star and plate forms but some periods of riming conditions tipped the scale towards a higher density. Despite the light wind speeds, snow was moving around a good bit yesterday with drifts developing mid slope. Look for drifting and slabs forming in what may normally be a preferred ascent route such as along the right side of Right Gully. Although not in the lee of the prevailing wind, these smaller terrain features may have developed areas of new slab as well.

Copious snow lately has deposited a lot of snow on the mountain with 62” (158cm) total at the snow stake at Hermit Lake. For comparison, the deepest recording last year was 161cm on March 22. Looking around the our forecast area you wouldn’t think the snow total this year is so close to that benchmark considering that most of our bed surfaces have really just recently grown to the point that rock and bushes are buried. Lobster Claw just grew to the point of being skiable and some areas like the Lower Snowfields have many shrubs and trees showing. Mostly low density snowfalls and plenty of scouring wind speeds have moved this year snow around.

The John Sherburne Ski Trail is in good condition right now. The Winter Lion Head Route opened recently and is the preferred shortest route to the summit.

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 7:55 a.m. February 9, 2015. 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

2015-02-09 print friendly