Avalanche Advisory for Monday, April 20,2015

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Low avalanche danger. Natural and human-triggered avalanches are unlikely.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEM: Temperatures will hover around the freezing mark in our Ravines today with wet snow and rain creating the potential for wet loose avalanches. Keep a close eye on the type and rate of precipitation since it will determine if more significant avalanche problems will develop. It is conceivable that the 3-6” (7.5-15cm) of snow and sleet forecast for the summit will create wet slab issues as rain begins to fall on the new snow. This could push our rating into a Moderate danger rating with human triggered avalanches becoming more likely in the steepest terrain.

OTHER HAZARDS: The usual spring hazards are in full bloom this week.  Large flows of ice have numerous areas where horizontal cracks are forming and the Sluice ice, above Lunch Rocks, is already missing some chunks. Rain will undoubtedly spawn more falling ice as it weakens the ice-to-cliff bond and melts channels through ice columns. Reduced visibility due to summit fog, flat light and snow will challenge navigation as well as your ability to identify and manage objective hazards. Additionally, the snowpack is slowly gliding downhill as a unified mass and is pulling away from cliffs, creating crevasses and moats. These may change quickly, and though many filled in with sluff debris yesterday, they will now doubt grow larger with this week’s weather. Undermined snow is creating challenges for exiting the Bowl and will become more undermined and more dangerous with increased meltwater and runoff. While the Little Headwall is still skiable, there is open water both above and below, with large moguls throughout. The safer exit from the Bowl is to carry your skis down the hiking trail to HoJo’s where you can easily pick up the Sherburne Ski Trail. As of yesterday, it was just possible to make it to the parking lot, though the riding involved threading the needle through bare patches while raking your bases over exposed rocks. It may be best to cross back over to the Tuckerman Ravine trail as the snow disappears. Please respect our advice when we string the rope across the ski trail…foot traffic damages the trail and leads to erosion.

WEATHER and SNOWPACK: After perfect spring conditions yesterday, the weather is taking a turn for the worse. Precipitation will start around lunch time with wet snow before changing to sleet, freezing rain and then rain tonight. High winds and fog will challenge visibility and make for unpleasant above tree-line travel, but I don’t expect this wet snow to be moved along the ground and drift into the wind slabs that you would see in colder, drier winter conditions. A slushy surface is the most likely conditions you will find today with firm and less edge-able snow beneath in some areas. Unsettled weather is on tap all week with proverbial April rain and snow showers expected most days.

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 7:45 a.m., Monday, April 20, 2015. A new advisory will be issued tomorrow.

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

2015-04-20 print friendly