Tuckerman Ravine has MODERATE and CONSDERABLE avalanche danger. All forecast areas have Considerable avalanche danger except the Little Headwall and the Lower Snowfields which have Moderate danger. Natural avalanches are possible and human triggered avalanches are likely in Hillmans Highway, Left Gully, Chute, Center Headwall, Sluice, Right Gully and Lobster Claw. Natural avalanches are unlikely but human triggered avalanches are possible in the Little Headwall and Lower Snowfields.
Huntington Ravine has CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely in all forecast areas. Careful snowpack evaluation, cautious route finding and conservative decision making are essential for those traveling in Huntington today.
Avalanche danger will be increasing through the day as 3-6” of snow, possibly mixed with sleet later on, fall in 55-75mph southwest winds.
Overcast skies this morning allow another look at the snowpack in the Ravines before a warm front reduces visibility with lowering clouds and blowing snow later today. The forecasted snowfall will add to our existing avalanche problem in areas previously loaded by the most recent Nor’easter and create new windslabs in areas that were scoured down to old surface during the same storm. Additionally, light snow deposited in the many lee areas and nooks and crannies of the alpine zone will be picked up by the increasing winds and dropped into the start zones of areas like Hillmans Highway, Left Gully, the Chute and Center Headwall in Tuckerman Ravine and South Gully, Odell, Pinnacle and Central Gully in Huntington Ravine. Recall that these areas and others which face generally North and East were scoured out during Friday and Saturdays Nor’easter to the point that old surface rain crust will form today’s bed surface in those areas. The incoming snow, which will increase in density, will form sensitive windslabs with the dreaded “upside-down” configuration. While wind speeds will be high enough for loading in North and northeast aspects with new and transported snow, it will not reach speeds necessary to scour out more Southerly aspects. These East through South facing aspects will crossload strongly with the new snow adding weight to existing windslabs and cornices currently found out the top of areas like Right Gully, Lobster Claw, Yale and Damnation.
Those motivated to tangle with the white dragon had better be near the top or out of any gully by early afternoon. Avalanche issues today are complex and will only become more so as this storm develops. Travel in avalanche terrain is not recommended for climbers or skiers without extensive experience making route finding decisions in avalanche terrain in unstable snow. Speed will be paramount for climbers or ski mountaineers in the Ravines today. If your pack weighs much more than 25 lbs or if all of the gear you are carrying is shiny and new, you should rethink your plans for traveling in avalanche terrain today. Those with solid judgment and impeccable technical skills could scoot up and down steep terrain this morning before said dragon descends looking for victims. This morning, our snowpack is generally more stable than yesterday so risk tolerant individuals could find some adventure if they carefully consider the instabilities Chris wrote about in yesterday’s advisory. The choice is yours.
Those intending to summit via the Lion head (Tête de Lion) trail should be prepared for increasingly challenging travel conditions as winds ramp up and visibility degrades. Remember that the trail is a steep mountaineering route and recent snow will make the rock step easier while deeper and drifted snow above treeline may slow your pace.
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 8:42a.m. 2-11-2013. A new advisory will be issued tomorrow.
Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856