Avalanche Advisory for Thursday, 4-05-2012

This advisory expires at midnight, Thursday 4-05-2012

Tuckerman Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to lack of snow. Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

Coming in right on schedule, new snow started falling very late Wednesday afternoon giving the mountain 1.3″ by around midnight.  Since then, a bit more has fallen riding in on a strong NW wind gusting to hurricane force (77-80mph/120-128kph).  A slight chance of snow showers will continue today with increasing fog and continued windy conditions.  Summit temperatures will continue to stay quite wintry for the week ahead, moving from the teens today down into the lower single numbers overnight before rebounding slightly again tomorrow.  An ever-so-slight increase over the weekend will help the comfort level a little, but anticipate the summit to only reach the 20F degree mark.  Isolated areas of newly deposited windslab from the past 72 hours of light snow are slow to consolidate with the cold air in place and high winds.  Remember to constantly re-evaluate each new area of cold slab you enter and not presume it was as stable as the last one you traveled through.  This is particularly true on steeper or in more protected terrain features from W and NW winds.   Additionally, be thinking about your changing fall line and runout. A small slab that knocks you off your feet may not bury you, but the consequences of a fall can be severe.  One of the current problems that will greatly exacerbate the hazards in the Ravine is the potential for dropping clouds and fog.  Historically this has caused a number of accidents because it is very difficult to assess hazards if you can’t see them.  This is particularly true trying to ski or ride in areas with crevasses or deal with falling ice moving at 50mph down slope when you can’t see it coming.  For many seasoned mountain travelers fog is a “red light-no go” indicator.

Crevasses, undermined snow, and waterfall holes continue to be a serious threat. Currently the area from the Sluice to the Center Bowl is littered with crevasses. Most of these are covered with a thin coating of newer snow, which makes them nearly impossible to safely assess their exact location, size and depth. The hazards presented by the crevasses are not to be taken lightly; it is truly “no-fall” terrain. Taking into account the extent of crevasses, the severity of the consequences, and the inability to assess the hazard, the greater LIP area, which includes a section of the summer hiking trail should be avoided entirely.  This is also true for the heavily crevassed areas in the northern portions of the Center Bowl underneath the headwall ice, Lip and areas towards the Sluice all the way down to the Ravine floor.  Foggy conditions will make all these problems worse.

Surfaces will be icy and hard below the new snow, so long sliding falls continue to be another significant threat. The slick surface will allow for rapid acceleration down slope, potentially sending you into numerous obstacles below you. An ice axe, full 10-12 point crampons, and real mountaineering boots are absolutely critical for climbing in these conditions safely. The hard surface beneath the new snow makes roped climbing with anchors on the steeper slopes a wise technique in certain situations. Because the current surface conditions have made most steep slopes “no fall” territory, the ability to use technical mountaineering skills and equipment effectively is imperative.

Even though temperatures this week will not be very warm, falling ice is a possibility. This was exemplified yesterday as ice fell out of the Sluice and crashed through Lunch Rocks (aka “Icefall Rocks”) There is a lot of recently formed ice from the cold weather over the past couple weeks. Your best defense against falling ice is to avoid being anywhere near the possible runouts. The locations at greatest risk for this hazard are the Sluice, Lunch Rocks, the Lip, and the Center Bowl. Other areas aren’t immune though, so always be aware of what’s above you. The Harvard Cabin is now closed for the season. The only camping permitted on the eastern side of Mount Washington is at Hermit Lake Shelters. The Sherburne Ski Trail is open about 1/3 of the way down; please cross over to the hiking trail at the rope.

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, the caretaker at Hermit Lake Shelters. A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service, White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

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