Avalanche Advisory for Thursday, March 22, 2018

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

AVALANCHE PROBLEM: A low pressure system passing to our south and east may generate 2” of snow today on the mountain. This snow will fall on N and NE winds and may build and cross-load small wind slabs in sheltered locations, particularly northern gullies in Huntington and the right side of Tuckerman Ravine. Any wind slabs that build will be on a very firm, and in most places, smooth snowpack. The hard snow surface will increase the likelihood of triggering a small wind slab and raise the consequences if you were to be surprised or swept off of your feet. If you are playing in steep terrain, an ice axe and crampons will make you feel a lot more secure due to the hard and just barely edge-able snow. Though wind slab may be the primary avalanche problem, a long sliding fall is a close second on the list of hazards.  

WEATHER: It is 20F at Hermit Lake this morning and 16F on the summit with relatively light easterly winds in the 40mph range. Winds will increase to the 50-70mph range as they wrap around to the north through the day. Expect temperatures in the high-teens F on the summit with a chance of snowfall bringing up to 2”, though likely less. Summit fog may obscure visibility at times. Certainly not a bluebird day on tap for this early spring day, but not a bad day to be out and about.

SNOWPACK: It’s been four days since any measureable precipitation fell on the summit, though cool temperatures between 0 and 20F have preserved this new snow well. Sixty-five inches of snow has fallen so far this month on the summit accompanied by colder than normal temperatures, allowing our snowpack to bounce back a bit from the deficit we entered in January and February. There is currently 173cm of snow at the stake at the Hermit Lake snowplot. With a warm and dry pattern in the long-range forecast, who knows how long the snowpack will last. The 30” snowfall last week and the howling 100mph+ westerly wind that followed filled out the slopes and runouts in an impressive way. For now, Tuckerman Ravine is in pretty good shape, though gullies on the right side still have limited coverage despite having enough bed surface to generate avalanche activity there during the last avalanche cycle. Snow surfaces are predominately hard, but pockets of softer snow, some of it covered by a thick and grabby wind skin, exists in sheltered locations like the edges of gullies. This variability will keep you on your toes when skiing or climbing, especially considering the hard surface in most fall lines.

The Sherburne Ski Trail benefited greatly from last week’s snowfall. Great coverage exists, though a bit of scouring may have exposed a rock or two in the usual wind hammered sections.

Be sure to check out our Instagram posts (@mwacenter) for up to date photos and videos. You don’t even need an account to view them online if you are trying to avoid social media!

The Harvard Cabin will be open all nights this week.

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 8:10 a.m., Thursday, March 22, 2018. A new advisory will be issued tomorrow.

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