Avalanche Advisory for Friday, February 23, 2018

This advisory expires at midnight.

Huntington and Tuckerman Ravine will have LOW avalanche danger today. Generally safe avalanche conditions exist for all forecast areas.

AVALANCHE PROBLEM: This morning, there is no avalanche problem. Avalanche terrain consists of refrozen snow that with its hard, icy surface, will require the use of crampons and an ice axe to navigate safely. Long sliding falls are currently the greatest danger. Up to 2” of snow is forecast on increasing SW wind in the afternoon and will create areas of wind slab. If we receive the upper end of the forecast snow total, areas in the lee of SW and W wind may exceed the current Low rating.  Be aware of this in Hillman’s Highway, Left Gully and the Chute in Tuckerman as well as Escape Hatch, South and Odell in Huntington. Warming temperatures late may mix sleet and freezing rain into this snow, adding a wet layer to the snow surface. Travelers out late in the day should keep an eye on the sky and be prepared to re-evaluate plans if we receive the upper end of forecast totals.

WEATHER: Yesterday consisted of scattered clouds and a mild NW wind. Temperatures at Hermit Lake and the Summit both saw a maximum in the low 20sF. Lingering high pressure this morning will keep skies largely clear with mild winds and temperatures in the 20sF. Incoming low pressure this afternoon will allow fog to develop on the summits. Current W wind of 25mph will shift to the SW this morning and steadily increase through the day to 50-70mph. Once darkness arrives, the wind will shift to the W and eventually NW by midnight. Snow showers are likely before the temperature rises enough for a transition to mixed precipitation. The amount of liquid precip should remain low, with up to 0.15” by midnight. If we receive the high end of forecast precipitation, we may see 2” of snow.

SNOWPACK: Record-setting temperatures Tuesday and Wednesday were followed by a freeze Wednesday night. This has stabilized our snowpack and created icy surfaces in avalanche terrain. If you venture off-trail in the woods, it may still be possible to post-hole in areas, though above-treeline surfaces should remain solid. Traction is necessary even on flat trails at the moment. The Little Headwall is now an open river and no longer an option for skiing out of Tuckerman Ravine. The Sherburne has stretches of bare ground and water ice. Be prepared to remove your skis at times on the way down.

• 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 Harvard Cabin.
• Posted 8:10 a.m., Friday, February 23, 2018. A new advisory will be issued tomorrow.

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