Avalanche Advisory for Saturday 12-29-2012

Expires at Midnight Saturday, 12-29-2012

Tuckerman Ravine has LOW and MODERATE avalanche danger.  The Lobster Claw, Right Gully, Sluice, Lip, and Center Bowl have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Evaluate snow and terrain carefully to identify features of concern.  The Chute, Left Gully, and Hillman’s Highway have Low avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated terrain features.  We are not forecasting for the Lower Snowfields and the Little Headwall due to a general lack of snow. Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

Huntington Ravine has LOW and MODERATE avalanche danger.  North, Damnation, Yale, Central and Pinnacle gullies have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Evaluate snow and terrain carefully to identify features of concern.  Odell and South Gully have Low avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated terrain features.  We are not forecasting for the Escape Hatch due to a general lack of snow. Forecasting will begin when conditions warrant.

Although no new snow fell during the day on Friday a brisk NW wind loaded Thursday’s Nor’easter storm snow back into the Ravines.  Although clear in the valley, we were desperately waiting out low visibility and blowing snow for a safe opportunity to get in the Ravines.  A brief window gave us some glimmers of Tuckerman, but Huntington’s view held out until this morning.  What we witnessed was enormous loading into S aspects from E, NE, and N storm winds.  This caused Connection Gully to avalanche and filled in the Lobster Claw and Right Gully. The Bulls-eye for new loading yesterday occurred on SE facing slopes.  A natural avalanche was triggered in the Lip during the early afternoon which ran down the “Open Book” and onto the Ravine floor.  Loading continued with strong NW winds into the early evening.  Another avalanche crown line was witnessed below the earlier fracture this morning which likely occurred during the overnight. 

The main points for today:

**Generally, many snowfields are still growing to their typical size and continue to be isolated from their neighbors by brush, rocks, and ice.   A good route finder with avalanche skills can find reasonable lines to avoid instabilities.  However, it is important to recognize we have had recent natural avalanche activity in such pockets, mostly focused on SE facing slopes and below ice bugles.  Therefore be cautious and evaluate new areas of slab from the recent storm, particularly in areas forecasted at Moderate.

**In Huntington be particularly aware of unstable slabs on some approaches particularly below large ice bulges.  This was demonstrated by an avalanche that occurred yesterday below the initial ice in Odell.

**Areas posted at Low do have isolated pockets of concern near the top of gullies such as the climber’s right of Hillman’s and Left gully.  Also watch pockets in the lee of terrain feature changes mid-gully such as above the narrows in the Chute and in the central low angle portions of Odell.

** New snow is expected to begin this afternoon and pick up late in the day.  Snow will continue during the overnight bringing us 3-5 inches by Sunday morning.  Winds will begin light and travel counterclockwise from the NW all the way around the compass rose back to the NW again tomorrow.  As it travels it is expected to increase in velocity and be raging in the morning gusting to 100mph.  We don’t expect this to affect danger ratings today during daylight hours, but start thinking about a change of conditions this evening if you’re out late.  Tomorrow you can expect avalanche ratings to increase.

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 8:34am 12-29-2012. 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

12-29-2012 Print Version