Avalanche Advisory, Wednesday 1-11-2012

Expires midnight, 1-11-2012

Tuckerman Ravine has Moderate avalanche danger today. Natural avalanches are unlikely and human triggered avalanches are possible. Heightened avalanche conditions exist on specific terrain features; evaluate snow and terrain carefully and identify features of concern. The exception to this rating is Hillman’s Highway and Left Gully which have Low avalanche danger. Natural and human triggered avalanches there are unlikely. Watch for unstable snow on isolated terrain features. Some areas are not yet posted due to the overall lack of snow. These include Lobster Claw, Right Gully, the Lower Snowfields, and the Little Headwall in Tuckerman. Forecasts for these locations will begin when conditions warrant.

Huntington Ravine has Low avalanche danger today.   Natural and human triggered avalanches are unlikely except in isolated terrain features. The Escape Hatch is not posted due to lack of snow cover.

Some more loose change fell yesterday as the nickel and diming continues with 1.4” (3.5cm) falling on the summit.  The mountain has seen snow everyday this month adding up to 11”(27.5cm) over the past 11 days averaging 7.4% in density.  Averaging an inch a day certainly isn’t much, but believe it or not, it has been making a difference.  Because the Ravines have been filling so slowly it hurts to see our precious accumulations over the past week an a half get taken away. But never the less, high West winds yesterday reaching 94 mph (153kph) did a fair bit of scouring across the mountain, particularly in the gullies of Huntington Ravine.  A few isolated pockets exist such as down low in Central, but overall stable conditions exist.  Because of their thin ribbon like nature Yale, Damnation, and North appear to have gone through the most dramatic change due to high wind velocities over the past several days.  Their exits are most notably scant of snow with a number of rocks and terrain features peppering the slopes.  All of this has led to the drop from Moderate to Low avalanche danger in Huntington.  In Tuckerman the lower slopes in the Ravine are most wind affected and are generally stable, but as you ascend in elevation areas of instability, protected from the high prevailing winds, are a concern.  New slabs below the ice in the Sluice, through the Lip, the Headwall ice, and over into the Chute above the narrows have triggered us to forecast a “Moderate” rating.  The Lip has most notably been protected from the high winds and its scouring effects, picking up new snow from edge to edge across its entire forecast area.  This slope and its adjacent pockets lead the concern for harboring unstable snow in the Ravines today. 

The big news is the weather event moving into the region tonight expected to give us “plowable snow”, as the weather service calls it.  It’s becoming clear that we will get something to enjoy, perhaps around 6-7 inches (15-17.5cm) delivered on SW, shifting to SE, winds.  This will affect north facing aspects the most on Thursday and into Friday morning.  Although it may be a bit premature to discuss Friday night I’ll mention it any way.  All models are showing a wind shift moving from the south to the west and increasing dramatically as we enter Saturday.  This would give us new problems as we enter the holiday, but more on that issue over the next 48 hours.  With the precipitation beginning after dark tonight you can expect an increasing avalanche danger tomorrow.

 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 8:45a.m. A new advisory will be issued tomorrow.

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

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