Avalanche Advisory for Saturday, April 22, 2017

This advisory expires at Midnight.

Huntington and Tuckerman Ravines have LOW avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features. Generally safe avalanche conditions exist.

AVALANCHE PROBLEM: Surface loose wet sluff avalanches remain our primary stability concern, with recent precipitation and temperatures just above freezing allowing continued development of uniformity deep in the snowpack. Upper elevations of our forecast areas may have seen a refreeze overnight, but we do not expect particularly firm snow conditions for much if any of Tuckerman or Huntington Ravines today. The wet sluffs that a skier or rider may initiate on steep slopes could be heavy and may be difficult to escape; be mindful of terrain hazards in the fall line below you. Additionally, the remote possibility of a large deep slab avalanche, with a sliding surface lubricated by flowing meltwater, will remain through much of spring.

WEATHER: Precipitation fell for the majority of the day yesterday in the form of ice pellets and freezing drizzle, totaling 0.27” of water. Current weather on the Summit is 31F with a W wind of 30mph. Low pressure lingering over the region for the day will prevent clearing and continue light mixed precipitation for the day. Temperatures will hover around the freezing mark for the morning and eventually drop in the afternoon to the 20sF, allowing precipitation to turn to snow by evening. By day’s end, 1-3” of sleet and snow may accumulate. Tonight, high pressure will push the dreary weather out, creating a bluebird day tomorrow, perfect for spring skiing.

ADDITIONAL HAZARDS:

  • Long sliding falls While there is the feeling of spring in the air, winter gear is still essential for climbing and skiing on the mountain. Snowshoes and microspikes are no substitute for crampons and an ice axe. Arresting a fall on an icy 30+ degree slope can be practically impossible. Keep in mind what is below you when moving around.
  • Crevasses or glide cracks, moats and waterfall holes – Glide cracks, our version of crevasses, form when the snowpack gradually creeps downhill. As the snow pulls away from a cliff, this creates a gap that could swallow a person. Several slopes in our terrain are becoming crisscrossed with these and glacier travel techniques could be helpful. Large holes are also forming due to undermining by meltwater. Falling into the waterfall hole in the Lip or even one of the holes in the Little Headwall area can have dire consequences.
  • Icefall: This hazard is unpredictable but above freezing temperatures certainly increase the risk of ice releasing from a cliff. Ice will fall, roll and slide with surprising speed at times. Don’t count on your ability to dodge this hazard. It is best to reduce your risk by reducing time spent beneath frozen waterfalls. As we move forward, remember that Lunch Rocks is in the bullseye of the massive ice in Sluice which makes hanging out there a high stakes game of roulette.

The Lion Head Winter Route is still open. If skiing or riding in the Bowl and heading down, please walk down the Tuckerman Ravine Trail to Hermit Lake where you can then get on the Sherburne Ski Trail. The rope is up at crossover #3, about a half mile from Pinkham. Please respect the rope and move over to the hiking trail to avoid wallowing in mud.

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 caretaker at Hermit Lake Shelters.

Posted  7:40 a.m., Saturday, April 22, 2017. A new advisory will be issued tomorrow.

Ryan Matz / Helon Hoffer, Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2017-04-22