Avalanche Advisory for Saturday, April 5, 2014

This advisory expires at Midnight.

Tuckerman and Huntington Ravines have MODERATE avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully.

AVALANCHE PROBLEMS:  Wet Slab avalanches due to last nights rain and continuing mixed precipitation will remain the number one concern until temperatures drop further this afternoon. Storm Slab and Wind Slab may take over as the primary threat later today as new snow falls with the potential to quickly build slabs in lee areas. 

WEATHER:  An occluded frontal passage continues until later this morning when warm moist air begins to clear out, making way for colder air. Total precipitation amounts are challenging to predict with this occluded front and upslope flow which follows. Afternoon upslope flow will wring out the remaining moisture bringing snow shower activity to the mountain. History has shown upslope snow shower activity can bring enough precipitation to cause a wind and storm slab avalanche problem. Expect reduced visibility most of the day due to fog and mixed precipitation then, summit fog and snow showers. High winds will develop through the day, eventually reaching 50-70 mph in the afternoon and even higher in the evening hours. Temperatures will fall to the mid-teens F (-10C). Wind will shift to the west from the current southwesterly direction. Tomorrow looks to be a much nicer day in the mountains.

SNOWPACK: Yesterday warm temperatures and sunny skies worked their magic on our terrain and yielded a bumper crop of corn snow. Sluff runnels and piles of snow grains are freezing into death cookies as I write. A short inch of snow with a glaze of ice fell after the rain last night at Hermit Lake and has refrozen near the surface. Many areas, particularly sheltered unpacked areas, will be punchy for a while this morning until cold penetrates the surface and reduces postholing problems. Expect horrendous skiing conditions and long sliding fall potential today. Nearby ski trails will be good alternatives until  later in the day when they freeze up. Some new snow may freshen things up on these trails but the extent and timing is pretty uncertain. Rain and melt yesterday may be building hydraulic pressure and causing ice dam issues on ice climbs so stay aware of this hazard if headed up to do a route.

Icy, refrozen snow on higher and steeper terrain will limit penetration of boots or skis. Crampons and an ice axe are recommended for travel on steep slopes. Micro-spikes and other creeper style traction devices may be helpful on some lower angle trails, but they do not provide the security of crampons.  Also be on the lookout for undermined snow bridges and open holes over stream beds. The Harvard Cabin is closed for the season.

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. Posted 8:00 a.m. 4-5-2014. 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

2014-04-05 Print friendly