This advisory expires at 12:00 midnight.
Tuckerman Ravine has Considerable and Low avalanche danger. The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway will have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. All other forecast areas have Low avalanche danger. Expect heightened avalanche conditions on specific terrain features.
All forecast areas of Huntington Ravine have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely.
AVALANCHE PROBLEM: Wind slabs that developed since yesterday afternoon will create our primary avalanche hazard today. Winds will blow today’s new snow, and snow sitting above treeline, into our avalanche start zones and create more wind slabs. Limited visibility, until some clearing begins around noon time, will limit observation and challenge terrain assessment.
WEATHER: A cold front moving though our area yesterday brought high winds to the Presidential Range for the first time in several days. Wind velocity grew through the afternoon and evening hours, ultimately yielding a peak gust of 95 mph. The wind wrapped from the South to the West as it grew in intensity helping it access most of last weeks new snow, even where it was hidden in lee areas. Wind slabs grew large and though there is limited visibility currently to confirm this, there are likely many signs of recent natural avalanche activity. A snow ranger observed a natural sluff in the left side of Center Bowl trigger and propagate a shallow slab around noon yesterday before loading really even got going. A trace to 2″ new snow is possible today and may even yield more in localized areas if anticipated potential snow squalls pan out.
SNOWPACK: 2.5″ (6cm) of low density snow fell yesterday and was blown into our start zones by stout winds in the 75 mph range. Wind will continue at an effective loading speed (45-60 mph) and direction (West) today. This will continue adding layers to the wind slab layer cake. A number of different density layers, mixed in with several potential weak layers, all rest on a hard icy old surface. Wind slab that grew yesterday could produce large human triggered and possibly natural avalanches in many areas. The Considerable rated areas in Tuckerman are places to avoid traveling today. Other areas in Tuckerman may be more scoured due to a peak 95 mph wind. However, you’d have a hard time tip toeing through sluff pile slabs at the base of steep sections and thick wind slabs in lee areas to find them.
OTHER HAZARDS: There is still a lot of ice and hard crusts out there hidden by new snow. Ski poles and various foot traction will be helpful getting to Hermit Lake or the Harvard Cabin in some areas. Crampons and an ice ax are essential for travel in steeper terrain. The Lion Head Winter Route has limited snow cover, so it is a very steep icy mountaineering route at this time. Expect crowded slow moving conditions as people try to negotiate the steep sections safely.
- 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 8:35a.m. Monday 1-20-2014. 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