Avalanche Advisory for Wednesday, January 31, 2018

Huntington Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features. The Little Headwall is not rated due to a lack of snow.  The Lip still contains a large void in the snowpack from the wet avalanche on January 12 or 13.

AVALANCHE PROBLEM: A firm and icy snowpack with some areas of mostly stubborn wind slab mark our terrain. These wind slabs are unlikely to produce an avalanche but are worth evaluating for signs of a weak bond to snow beneath and a tendency to sustain a crack along the surface. The wind slabs in question are easily visible and identified by contrast to the gray and dirtier looking, refrozen snow. You may find these slabs beneath steep pitches of ice and in other wind sheltered locations.

WEATHER: The temperature at Hermit Lake this morning is -2F and -10F on the summit with a NW wind in the low 60’s mph and gusting to 70 mph. Temps on the summit will warm to around 10F by nightfall as winds shift to the southwest. Wind speeds will diminish through mid-day before ramping up again as southwest flow brings clouds and light snow. Snow will start late in the day so is unlikely to create avalanche concerns though visibility may be reduced by snowfall and flat light. Scattered snow showers or light snow will continue through tomorrow and may refresh the snow coffers at higher elevations with up to 4-6” new snow by Friday morning. West winds combined with the new snow may create some unstable wind slabs tomorrow and Friday.

SNOWPACK: The dominant feature of the snowpack remains the widespread knife hard, ice glazed surface. Crampons are necessary to climb beyond low angle terrain due to this slick, hard surface. Stability tests and travel in Left Gully to the choke, about ¾ of the way up, last weekend showed that the older wind slab was well bonded to this icy surface. Nearer the surface, firmer (1F) wind slab over the thicker 4F slab created a clean shear at the interface between these two layers but neither layer showed any desire to propagate a crack much beyond your feet. No avalanche activity has been reported in these wind slabs. Elsewhere, the firm snow provides for quick and efficient cramponing but is an unforgivingly fast surface if you stumble so stay vigilant!

Microspikes and crampons are key tools for travel today. Crampons are needed on the steeper slopes and above treeline. Conditions on the Sherburne Ski Trail remain grim though passable for those desperate for a lap. Seems like the folks running to and from Hermit Lake and the summit yesterday had the right idea.

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 Harvard Cabin.
• Posted 7:30 a.m., Wednesday, January 31, 2018. 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