Avalanche Advisory for Saturday, April 26, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely. Be prepared for increasing avalanche hazard if snow falls heavier than forecast.

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: Earlier this week we received a small amount of new snow, which was blown into S and E facing slopes as well as pockets just about everywhere else. Yesterday all of this new snow warmed and then was chopped up by numerous skiers and riders. This snow has since gone below freezing and provides the groundwork for what will come today. Today we are expecting new precipitation. If this comes as all snow, and if we exceed the upper range of what is forecast, avalanche danger may rise above today’s Low rating in some areas. With a roughly textured bed surface, the forecasted snow totals, and relatively light winds, I do not expect there will be enough slab development to become a widespread problem. As always though, you need to watch the actual weather yourself and be responsible for your own decisions based on your assessments!

WEATHER: The big question about the weather is this: At what elevation will the line be drawn between frozen precipitation and rain? We are almost certainly going to get some precipitation today, but whether this comes as snow, sleet, or rain will be something you will need to pay attention to. You should be expecting rain, between 0.2 and 0.3” (~1cm) at elevations with temperatures above freezing. This may translate to 1-3” (2.5-7.5cm) of snow where it falls as all snow. Winds will be from the S and decreasing to 10-25mph. Also be prepared for very limited visibility in the thick fog.

SNOWPACK: As mentioned, there is a mix of old surfaces and relatively new snow from earlier in the week. The new snow adhered well in locations where it had loaded, allowing many skiers to carve it up yesterday while it was warm. Both the old surface and the new snow have good stability.

OTHER HAZARDS: Long sliding falls are a potential hazard today snow surfaces stay frozen. An ice axe and crampons will help keep you safe, but knowing how to effectively use them is every bit as important. Practice before you put yourself into “no-fall” terrain. ICEFALL is a possibility today. Rain is often a trigger for falling ice. In low visibility you cannot see it coming at you. This hazard will be increasing if it warms or if we have rain. CREVASSES have been late in emerging this season. Currently they are mostly buried and not a problem. The most notable exception to this is in the Lip, other smaller holes exist in Sluice and elsewhere. There is also some undermined snow in Right Gully and Lobster Claw.

The Lion Head Winter Route is still open. This is a steep icy trail. An ice axe, crampons, and the ability to use these tools effectively are highly recommended. Lightweight trail crampons lose their effectiveness in terrain this steep!

The John Sherburne Ski Trail is open to about 1 mile from Pinkham and closed below this point. Expect lots of bare patches, icy sections, and enormous bumps throughout the 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 caretakers at Hermit Lake or Pinkham Notch Visitor Center.
  • Posted 7:15 a.m. 4-26-2014. A new advisory will be issued tomorrow.

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

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