Avalanche Advisory for Saturday, 3-31-2012

This advisory expires at 12midnight, Saturday 3-31-2012

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Sluice, Center Bowl, and the Chute have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions exist on specific terrain features.  Evaluate snow and terrain carefully to identify features of concern.  The Right Gully, Lip, Left Gully, and Hillman’s Highway have Low avalanche danger.  Natural and human triggered avalanches are unlikely except in isolated terrain features.  The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to lack of snow. 

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down. 

Since last weekend the summit picked up snow everyday this week adding up to about 13.5” (34cm).  Sounds great doesn’t it?  But when you start looking around you’ve got to wonder where it all went.  Plenty of old surface is peppered around all our forecast areas intermingled with small to large patches of new snow.  Although it doesn’t quite feel like we received over a foot up high, we do have new snow issues to contend with, albeit limited to specific areas.  I was close to calling all forecast areas at “Low” this morning.  However one significant factor pushing me into “Moderate” for a few locations is the potential for a high number of triggers (i.e. you and your friends) running around due to it being a “Spring Skiing” Saturday.  More triggers covering a given area increase the possibility of finding the “sweet spot” or weakness on a given slope.  Although we don’t have a lot instability concerns, if skiers and riders hit most of the new slabs in Tuckerman today there is a possibility of a human triggered avalanche.  The largest pockets we are focused on as problematic are in the Sluice below the ice which has already seen some foot traffic; above and below the Headwall ice and down low under the Lip in the Center Bowl; and in the Chute above the pinch point in the hour glass.  As individuals enter these locations I would be cautious about being under these slopes in the runouts.  Enough snow exists in some of these snowfields to bury a person.  Besides avalanche issues, the other problem the new snow is contributing to involve hiding a number of crevasses, mostly in the Headwall ice area and particularly under and near the Lip.  Because of this The Lip continues to be not recommended as falling into one of these holes could be very dire.  Left Gully and Hillman’s will be hard and icy, but are the best choices relative to your other options around the Ravine and the hazards they harbor. 

Cold air is still controlling the mountain.  The old grey colored surfaces are very hard, so long sliding falls are a significant threat to all mountain travelers in angled terrain. The slick icy surface will allow for rapid acceleration down slope potentially sending you into numerous obstacles below you. An ice axe, full 10-12 point crampons, and real mountaineering boots are absolutely critical for climbing in these conditions safely.  Because the current surface conditions have made most steep slopes “no fall” territory, the experience and skills to use this equipment is imperative.    

The annual undermined snow and crevasses exist around the Ravine. Overall, the worst of the crevasses can be found in the Sluice, through the Lip and into the Center Headwall. Undermined snow can be found in many locations.  Cold temperatures this week have strengthened snow in relation to these issues, but you’ll still want to know where they are so you can avoid them. Realize falling into an open crevasse from above is potentially more likely due to the icy surface conditions than when it’s soft.  We recommend climbing up what you plan to descend so you can learn about these hazards.  As we already mentioned, expect new snow to be hiding a number of crevasses. Falling ice should remain in the back of your mind as well. Below-freezing temperatures generally pose less risk than very warm days, but the freeze-thaw cycles can work to dislodge rock and ice from steep terrain, sending it onto anything in the runout. Solar rays on dark colored rock can loosen newly-formed ice even if temperatures remain below freezing.

 The Harvard Cabin will close tomorrow for the season.    The Sherburne Ski Trail, full of icy bumps coated in a few new inches of snow, is open about 1/3 of the way down.  Cross over to the hiking trail at the rope.

 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 Mount Washington Volunteer Ski Patrol, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.  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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