Avalanche Advisory for Tuesday, December 23, 2014

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Considerable and Moderate avalanche danger. The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Considerable danger. Natural avalanches are possible and human triggered avalanches are likely. Cautious route finding and conservative decision making are essential. The Lobster Claw and Right Gully have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Lower Snowfields and Little Headwall remain Not Posted due a lack of snow in these locations.

All forecast areas of Huntington Ravine have Considerable danger. Dangerous avalanche conditions exist. Natural avalanches are possible and human triggered avalanches are likely. Conservative decision making is essential.

AVALANCHE PROBLEM: You can take your pick of avalanche problems today. We’re looking at the potential for storm slabs, wet slabs, and/or wet loose avalanches today. These issues are coming as a result of new snow this morning which will likely transition to rain or freezing rain late today. Prior to today’s weather, we had been monitoring old wind slabs. These may become active again as the incoming weather system works to saturate the snowpack with liquid water. Keep this in mind, but for today you should focus your attention on the more immediate problems of new slab development and rain.

WEATHER: As of 8am, about 3″ (7.5cm) of new snow has fallen at Hermit Lake with slightly lower accumulations at Pinkham and the summit of Mt. Washington. The weather forecasters are calling for precipitation to change over to a mixed bag or freezing rain later today. In the ravines, the change is forecast to take place in the late afternoon or early evening. Until this happens, you should be expecting fresh snow falling on S or SW winds in the 25-40mph range (40-65kph). Temperatures will continue to rise through the night and into tomorrow.

The storm system that will be building over the next couple days is a significant one. If the worst-case scenarios play out, we may see upwards of 4″ of rain in favored upslope areas such as North Conway before Thursday morning. Needless to say, this is not a good situation for the snowpack anywhere in the North Country. Be sure to watch the avalanche advisory and weather forecasts carefully if you are planning to be out in the mountains over the next couple days.

SNOWPACK: With new snow falling on southerly winds, you should expect to see the most wind loading and slab development taking place in areas such as Hillman’s or Left Gully in Tuckerman and South and Odell in Huntington. Cross-loading will take place on slopes with a more easterly component, such as the Chute, Center Bowl, Pinnacle, and Central Gullies. All of these locations are prime candidates for avalanche activity to take place. On the northerly gullies of Huntington I would caution you to be aware of the potential for dry or wet loose snow avalanches, especially late in the day. Similar aspects in Tuckerman (i.e. Lobster Claw and Right Gully) are a lower concern due to their thin snow cover, as well as their aspect and lower slope angle.

There are a lot of variables at play today, such as snow totals, timing of the snow-rain transition, temperatures, etc. Each has its own influence on the hazard you’ll face if you’re in avalanche terrain. You’ll do well to focus on the fundamentals. New snow, winds at a favorable direction and speed for loading, and a change to rain or mixed precip should all be commanding your attention and influencing your decision making today.

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 8:25 a.m. December 23, 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

2014-12-23