Avalanche Advisory for Monday, February 17, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Considerable, Moderate and Low avalanche danger. The Sluice, Lip and Center Bowl have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Lobster Claw, Right Gully and Chute have Moderate danger. Natural avalanches are unlikely and human triggered avalanches are possible. Left Gully, Hillman’s Highway, Lower Snowfields and the Little Headwall have Low danger. Natural and human triggered avalanches are unlikely in these locations. Watch for unstable snow on isolated terrain features.

Huntington Ravine has Moderate and Low avalanche danger. Central Gully has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely. Beware of small avalanches in isolated areas or extreme terrain.

AVALANCHE PROBLEMS: After a day of high winds and low visibility, we’re able to drop a rating in most areas today. Wind Slabs continue to be the primary avalanche problem. Saturday night’s 4” (10cm) of snow formed slabs that were slowly eroded yesterday. The areas rated Considerable and Moderate were in the strongest lee areas of the WNW and NW winds and received more loading than scouring and have the most continuous areas of wind slab. Bear in mind that cold temperatures last night allowed very little strengthening of deeper weak layers so consider the potential for larger than expected avalanches and adjust your travel techniques accordingly.

WEATHER: You’d think that yesterday’s sustained 70-80 mph (113-129kph) winds would move all of the snow out of upper elevations, but the haze shrouding the ground is not clouds but plumes of snow. This indicates just how much snow is lying around following the Valentine’s Day storm, the 4” from Saturday night and also the lack of warm temperatures to assist the snow grains in bonding to one another. Northwest wind at 60-70 mph will decrease slightly through the day but gust higher as well. Sunny skies will provide little relief from the cold and wind today.

SNOWPACK: A couple of crown lines are still showing in the Lip and Right Gully/Sluice area, even after all the wind transported snow has blown in. The most remarkable sign of all the new snow moving around is the loading that has occurred in the Sluice throughout the Lip and Center Bowl area. The slab here is much more continuous than a few days ago and should be approached like you would a stranger in a dark city street…. warily, if at all. Better yet, cross the street and find an area with lower danger. Huntington Ravine, being slightly higher in elevation and less in the lee of the summit cone and was primarily scoured by the wind. Pockets of wind slab certainly exist in Low rated gullies as well as larger snowfields on some of the approaches so remain vigilant. Holiday traffic can be heavy so factor in the possibility of others dropping in on you in either ravine today. Keep the deeper persistent weak layers on your hazard checklist as well… they’re deeper now but still exist scattered around our terrain and would generate a dangerous avalanche if triggered.

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 8:45 a.m. 2-17-2014. 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

2014-02-17 Print friendly