Apr 242014
 

This advisory expires at Midnight.  

Although we just moved to a General Advisory during this midweek we are returning to a 5 Scale advisory. This is due to extent of the hazard in prelude to the weekend with additional precipitation over the next few days.  

Tuckerman Ravine has Considerable and Moderate avalanche danger. The Sluice, Lip, Center Bowl, and the Chute has Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  All other forecast areas in Tuckerman have Moderate avalanche hazard. Natural avalanches are unlikely and human triggered avalanches are possible.  The Little Headwall is an open waterfall and has no rating.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. We are no longer monitoring conditions. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEM: Wind Slabs and Storm Slabs are the main problem today due to overnight snow, snow today and high winds.  We expect a lingering avalanche problem due to this precipitation event and new rain/snow coming Friday night, Saturday, and Sunday.

WEATHER: As of midnight over 5″ fell in a short period and it has been snowing ever since adding an additional inch or two as of this morning.  Up to another 2″ is expected today.  High N winds will continue to build and shift, coming from the NW later today. Expect wind velocities over 100mph (160kph).   The cold air in the teens F, blowing snow, low visibility and very high winds have created full on winter conditions.

SNOWPACK: New snow is falling on an old rough and irregular melt freeze surface.  The hazard is almost exclusively in the new snow slabs that have developed over the past 12 hours and will continue to grow today.  Expect +/- 7 to 8″ of new snow on the summit to be loaded in on high winds causing slab development across all forecast areas.  Earlier in the winter when alpine areas are completely snow covered and bed surfaces are consistent and smooth we would have most areas bumped one rating higher.  But, between skier induced bumps and alpine bushes capturing some of this new snow, today’s ratings are appropriate.  Expect areas to be on the upper end of their rating depending how much new snow we receive exactly and what wind velocities we reach today.

OTHER HAZARDS:  With the current temperatures the icefall hazard has decreased a bit, but it should be on your mind, particularly the Sluice ice that looms behind Lunch Rocks.  Crevasses, that have begun to open up primarily in the Lip down towards Lunch Rocks, will likely be hidden by new snow making this hazard very difficult to assess.  The prudent traveler would avoid this areas due both to avalanche problems and crevasses.

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.
  • Posted 7:20 a.m. 4-24-2014. 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

2014-04-24 Print

 Posted by at 7:31 am
Apr 212014
 

This General Advisory expires at 12:00 midnight, Wednesday, April 23, 2014.

Tuckerman and Huntington Ravines are under a late season General Avalanche Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain. General Advisories are valid for no more than three days, but may be updated earlier as conditions warrant.

Each season we reach a point where the day-to-day avalanche hazard is not significantly changing. We have reached this point in the 2014 season, for this reason we have decided to shift to a General Advisory. We will be monitoring the ravines, though with less of a snowpack-focused approach than we have for the past several months. For you, as a backcountry traveler, this means that you are responsible for assessing weather, snow, and avalanche conditions (this is always the expectation, but now we will have less daily information for you to utilize.) New snow, rain, or other weather may cause stability problems to exist even under a General Advisory.

At the time of this posting, the snowpack in the ravines is very stable. It has seen multiple melt-freeze cycles, which have added tremendous strength to the snowpack. There are both very warm temps and some rain expected in the next few days, so be thinking about the effects of a lot of running water throughout the snowpack and in the streams.

FALLING ICE is a very dangerous situation. The largest ice looms in the Sluice above Lunch Rocks, in the Center Bowl of Tuckerman, and throughout much of Huntington. Other areas pose this threat as well, though to a lesser extent. The best advice we can give is to not spend time underneath areas where ice may fall. Large rocks may provide some cover, but they have proven themselves in the past to be inadequate shields for people hiding behind them. Lunch Rocks is a hazardous location when icefall is a possibility!

CREVASSES AND WATERFALL HOLES are another potentially lethal hazard. Each season these form in many areas, the worst are in the Sluice, Lip, and Center Bowl. Many of these holes follow stream courses under the snowpack with icy water spraying around. Sunday evening we received our first report of a climber breaking through and dangling her body into a crevasse, thankfully she did not fall all the way in, and was able to climb out.

UNDERMINED SNOW is related to the hazard above. It occurs when streams have eroded away the snowpack from below, but left behind a bridge of snow. This bridge can collapse without warning under your weight, bringing you into the icy stream below. Give wide berth to areas that have already collapse or show signs of sagging or cracking.

LONG SLIDING FALLS are probably the #1 cause of injury each spring. Cold temperatures cause the soft corn snow to refreeze into a slick and solid mass of ice. We always recommend an ice axe and crampons for travel in steep terrain. You may not need them always, but if the unexpected happens these tools, and the ability to use them effectively, can save you from serious injury or death.

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.
  • Posted 6:45 a.m. April 21, 2014. A new advisory will be issued Thursday, April 24.

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

2014-04-21 General Advisory

 Posted by at 6:46 am