Avalanche Advisory for Thursday, March 14, 2013

Expires at midnight Thursday, 3-14-2013

Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger today.  The Sluice, the Lip Center Bowl have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. All other forecast areas in Tuckerman Ravine have Moderate avalanche danger with the exception of the Little Headwall which has Low avalanche danger.  In Moderate rated areas, natural avalanches are unlikely and human triggered avalanches are possible.

 Huntington Ravines has MODERATE avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible in all forecast areas. Heightened avalanche conditions exist on specific terrain features.

Avalanche danger will be increasing  today due to new snow and wind.

It has been almost 30 hours since the summit recorded above freezing temperatures.  Since that time slush pools on the trail have frozen up and the free water migrating through the snowpack to the ground has by and large percolated through the snow. The snowpack has minimal boot penetration in areas that aren’t packed out though you can stomp a hole in the snow if you try.  Expect much harder and more slippery conditions in packed trails and areas that have seen a lot of ski traffic.  We are starting out the day with Low avalanche hazard in all forecast areas. That said, close to 1.5″ of a 50/50 mix of stellars and small graupel (rimed snow pellets)  in the 6% density range that fell since 6 pm yesterday are beginning to change things.

Currently, windspeeds are hovering in the high 30’s mph which is allowing the new snow to blanket the mountain with what could become the new weak layer.  The good folks at the Observatory have forecast 2-4″ more snow today with increasing winds.  If receive the upper end of the forecasted range of new snow, we will have an avalanche problem with natural avalanches becoming more and more possible. Today’s forecasted wind direction is WNW where it sits currently. If you listen closely, you can hear the snow particles sifting across upper starts zones and laying in pillows and small drifted pockets as the wind gusts over 40 mph.  Central, Pinnacle and Odell Gully already have and will continue to develop these areas of pooled and drifted snow as wind pushes more snow into upper start zones and sluffs further down the ice and steep rock slabs. Lee areas in all our forecast gullies will catch the drifting snow as the wind ramps up and deposits more snow into denser slabs. Any area behind a terrain feature that serves as a drift fence will allow snow to settle out of the wind.  Recall from your reading on avalanches, or your Level 1 avalanche course, that denser snow resting over lighter snow is a lemon or yellow flag. Another warning sign is active windloading.  And if you are out and about today and see fresh debris then you should really travel conservatively since that is a sign that natural avalanche activity is going on. Where there is one avalanche there may be more.

A total snowfall of 12″ so far this month has been recorded on the summit. Average total for the month is 54.1″.  For those of us looking forward to skiing in the spring, take heart, since winter ain’t over yet.  And by the way, Happy Pi Day.

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 8:35 am, March, 14th 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

2013-03-14 Print friendly