Avalanche Advisory for Friday, May 1st, 2015

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Lobster Claw, Right Gully, Left Gully, Hillman’s Highway, the Lower Snowfields, and the Little Headwall have Low avalanche danger. Natural and human-triggered avalanches are unlikely in these locations. Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington.

AVALANCHE PROBLEM: We have been continuing a slow moving trend towards more snow stability with temperatures above freezing during the day and below at night. Our field time today will focus on deep digging to conclude how the expected warm up over the next few days will effect wet slab and deep wet slab potential. Deeper areas of the newest snow from earlier in the week are rated Moderate due to concerns that further heating today, coupled with a slight chance of precipitation, continues the remote potential for Wet Slab avalanches.

OTHER PROBLEMS/HAZARDS: Be aware of the potential for crevasses to be hidden underneath the recent snow and the potential for falling ice. These issues will grow in intensity over the next several days due to the expected warming trend.  Although crevasses have been limited, they will grow in number and size quickly in the coming days.  These slots have already grabbed some people this week.

WEATHER: Fourteen days in a row of new snow has kept visibility low and intermittent as well as some avalanche conditions lingering on Mount Washington.  As unsettled weather tries to push out today, a clearing trend is expected which will feel like hot weather compared to the winterish April that concluded yesterday.  The prolonged period of low pressure systems that have plagued the higher terrain should give way to clear skies over the next 24 hours.  A chance of mixed precipitation once again exists today with a mix of clouds and sun. Temperatures will be in the mid thirties with a N wind, falling into the 10 mph range from a current of 25mph.

SNOWPACK:  New snow from early in the week has gone through some nice consolidation and sintering due diurnal swings above and below freezing. Today’s warm up will do more of the same, but will start a long period of around the clock melting with no nightly freeze up likely.  This has us thinking about meltwater percolating deeper than it has yet, bringing heat, more melting, and weakening into the week old snow that is quite deep in places.  This may increase the chance of wet slab avalanche problems in several isolated areas.  Our field time today will focus on this question and hopefully answer some of the nagging concerns regarding, “what will happen when it really gets hot out?”  The greatest concerns linger from the Sluice through the Left Center Headwall, with the bullseye being in the steepest open terrain from the Lip to the Center Bowl.  Continue to consider this hazard and your risk exposure in your field decisions and travel choices.  We are hoping for clear sky conditions to get a number of pictures up later today and don’t forget to look for the Weekend Update this afternoon.  We will provide an update based on what our field time tells us today.

The Little Headwall has open holes of water and undermined snow, but it continues to be a skiable option for descending from the Bowl. Expect this to change rapidly and may not be a good option by mid-weekend! Use extreme caution if choosing this route. Another alternative is to hike down to Hermit Lake, although expect an icy trail making microspikes and ski poles handy.  The John Sherburne ski trail will disintegrate rapidly so expect to hike more as the days get warm and be pleasantly surprised if you get to ski.  It’s currently closed at the #5 crossover, 1 mile up the Tuckerman Ravine Trail from the parking lot. At the rope, please avoid the muddy descent and cross to the hiking trail and walk down. Do not ski on the hiking trail.

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 Mount Washington Volunteer Ski Patrol, or the AMC at the Pinkham Notch Visitor Center and Hermit Lake.
  • Posted 8:15 a.m., Friday, May 1, 2015. A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713