Avalanche Advisory for Tuesday, February 4, 2014

This advisory expires at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully. The Lobster Claw, Right Gully, Lower Snowfields, and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine has Moderate and Low avalanche danger.  Central, Pinnacle, Odell, and South have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible. North, Damnation, Yale Gully, and the Escape Hatch have Low avalanche danger. Natural avalanches and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

AVALANCHE PROBLEMS: Once again, wind slab which developed during the night Saturday is the primary avalanche problem today. This formed as a result of about 4″ (10cm) of snowfall along with strong SW to W winds. It can be found in many locations and although it may be difficult to trigger, there is still enough potential for a person to trigger an avalanche. The odds of this happening are greater in locations most sheltered from westerly winds or in locations where recently buried rocks are creating weak points in the snowpack (e.g. upper Central Gully or the Center Bowl). Persistent slabs also exist, though they may not be found in all areas.

WEATHER: When you’re so desperately wanting new snow, it’s hard to see anything in the weather other than the WINTER STORM WARNING that starts late tonight. However, today looks to be a pleasant day on the mountain and should not be overlooked as a good day to get outside. High pressure is the dominant weather feature, bringing clear skies, relatively calm winds, and reasonable temperatures. Snow is not expected to begin until in the early morning hours on Wednesday. This will almost certainly affect snow stability for tomorrow, so be sure to check the weather forecast and avalanche advisory before heading into avalanche terrain.

SNOWPACK: Ratings are staying the same today as they were yesterday. This is because, well…because not much has changed since yesterday. Areas in Tuckerman posted at Low danger have very little snow in them useful for recreation. Huntington’s Low danger areas are more suitable for ice climbing, but they also have very little snow in the upper reaches. If you find newer drifts of snow in these higher locations, you should be very cautious around them. They are a good example of the “isolated terrain features” where unstable snow might exist under a Low danger rating.

Saturday night’s snow is the predominant surface layer around the ravines. It can generally be described as a stiff and brittle hard slab, about 1-finger on the hand hardness scale. In many locations, it’s sitting on top of snow that’s between 1-finger and 4-fingers hard. The slab showed good propagation potential, but the lack of a clear weak layer between the new slab and underlying snow makes it more difficult to trigger. Note that this is a generalization. There is a lot of variability in what this new snow is sitting on, so in many spots what I just said doesn’t isn’t perfectly accurate. The most concerning would be new slab sitting on top of a decomposing layer that has started to move towards facets. Pay attention to the various layers and take the time to assess your entire route as you travel through.

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 or the Harvard Cabin.
  • Posted 2-4-2014. 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

2014-02-04 Print Friendly