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 posssible. 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. Evaluate snow and terrain carefully. 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: Wind Slab which developed during the night Saturday is the primary avalanche problem today. These wind slabs loaded into start zones on a SW through W wind. Persistent Slab is a distant second problem which should remain in the back of your mind and move to the forefront on your list of concerns to evaluate in certain areas. Though the persistent faceted weak layer is widely scattered around our terrain, it could still serve as a fracture and initiation point for an avalanche in areas where it has not been scoured away by avalanche activity.
WEATHER: Improving visibility will allow visual recognition of areas of new drifted wind slab today as clearing continues with the approach of high pressure. Temperatures at the summit will be in the upper single digits F, around treeline in the teens F and, at the trailheads, in the low 20’s F. Summit wind is very light (18 mph 15 minute peak at 7:40 am) and expected to remain so today. The forecast is for diminishing clouds as well so we may even see a little sunshine today. Wednesday’s storm holds promise for the mountains with another potential storm Sunday night.
SNOWPACK: Yesterday, the mountain failed to receive the 1-3″ of new snow which were forecast and no natural avalanche activity occurred. That leaves us with Saturday’s new snow on top of areas of older wind slab over facets in some areas to contend with. The new snow is also covering a few areas of predominately old surface (Jan 11 rain crust) where avalanche activity has scoured out the intervening snow layers. The climbers left approach to Pinnacle, Center Bowl beneath the central hanging ice dagger, and the climbers left side of Left Gully to the choke point near the top contained long stretches of old boilerplate rain crust prior to this new snow. Additionally, almost all of North, Damnation and Yale had almost no snow in them prior to Saturday night’s 4.1″ so assessment and micro route finding will be easier there. The final stretch of Pinnacle as well as almost all of Central Gully contain areas with the greatest risk of a human triggered avalanche due to the load of new wind slab on older hard slab over facets. Upper parts of Odell and South Gully contain a similar risk. In Tuckerman, the Chute, skiers left side of Left and upper Hillman’s contain larger areas of the stubborn hard slab over scattered areas of facets with this new wind slab load on them and should be respected. Other areas rated Moderate will also contain similar characteristics in the snow so use your pole or axe penetrometer frequently to determine if the hard slab has softer snow or facets to serve as a weak layer.
- 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 8:30 a.m. 2-3-2014. 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