Latest avalanche advisory for Mount Washington’s Cutler River Drainage – Tuckerman and Huntington Ravines

Avalanche Advisory for January 19, 2017

This advisory expires at Midnight.

Huntington Ravine has CONSIDERABLE and MODERATE avalanche danger. Yale, Central, Pinnacle, and Odell have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. North, Damnation, South and Escape Hatch have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.

 Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. Sluice, Lip, Center Bowl, Chute, Left and Hillman’s Highway have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Lobster Claw and Right Gully have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.

Dangerous avalanche conditions exist today. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential in avalanche terrain.

AVALANCHE PROBLEM: Wind slabs developing in avalanche terrain are likely to be touchy today as the wind loads snow into the terrain. These wind slabs will develop over soft and weak snow which fell yesterday. To add to the danger today, our unstable snow rests on a very hard, refrozen snowpack. The firmness of this snowpack coupled with the many boulders and small cliffs that remain uncovered in the avalanche paths would make a fast and unpleasant trip if caught in an avalanche. Expect medium sized avalanches in Considerable rated areas that are capable of burying a person despite only 4.6” of new snowfall in the past 36 hours.

WEATHER: The increasing wind speed is the primary information to inform any travel decisions in avalanche terrain. In the past 24 hours, the summit recorded 2 inches of new snow with 4.6” total in the past 36 hours. During that same timeframe, winds from the SSE blew at just 20-30 mph. This morning the wind jumped up to the 50 mph (88 kph) range at around 7am and has shifted to its current position from the WNW. Currently, visibility is limited to a couple hundred yards due to dense fog and blowing snow. This morning will be a challenging time to make assessments of active loading but with the current wind speed and direction you can assume that the snow that fell in the past 36 hours is being moved into start zones of leeward slide paths.

SNOWPACK: Despite low wind speeds yesterday, snow was deposited and scoured to some extent. This means that we can expect some larger and more consequential wind slabs to exist in certain areas. Typically, wind speeds between 20-50 mph move snow into the mid to upper sections of most of our terrain. Due to shifted wind direction, you can expect to find wind slabs in a variety of locations. Also, this wind shift will access snow previously sheltered by lighter, southerly winds. The increased wind speed will also create more cohesive slabs that could be triggered by a person. Be cautious in any of our avalanche terrain today since sensitive wind slabs are likely to exist in one size or another in any area.

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 8:30a.m., Thursday, January 19, 2017. A new advisory will be issued tomorrow.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2713

2017-01-19

 

Avalanche Advisory for Wednesday, January 18, 2017

This advisory expires at midnight.

 

All forecast areas of Huntington and Tuckerman Ravine 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.

AVALANCHE PROBLEM: The primary avalanche problem will be Dry Loose avalanches. Soft Wind Slab may also develop behind terrain features and near the tops of gullies. We received just 3.5” of snow overnight. This has fallen on top of the old firm bed surface. Remember that the new snow is only a few inches deep and underneath is a crampon-worthy surface. Though snowfall totals are fairly meager, don’t underestimate the hazards of being avalanched on the hard bed surface lurking beneath the new snow.  Crampons and an ice axe will be useful, maybe even mandatory for ascending steep terrain today. With more snow on the way today and tonight and with winds forecast to increase tonight, beware of larger and more widespread wind slab to form after dark.

WEATHER: Clear skies, low winds, and sunshine were enjoyed by many yesterday. Clouds moved in last night with snow beginning around 10pm. During snowfall, winds shifted between the south and southeast, maxing at 30mph. Snow continues this morning at a rate of just under an inch per hour (S2). Snow will lessen in intensity through the morning, bringing another 1-3” by dark. Winds will shift between the south and southwest, staying under 30mph. Tonight, we may see up to another 3” with winds starting to increase.

SNOWPACK: Our bed surface for the current snowpack is the melt-freeze crust that formed last week. This is a well textured surface that is not uniform. In the steepest terrain, primarily in Tuckerman, scattered wind slabs formed on top of this old surface on Sunday. On top of these layers lies the new snow that started falling last night and will continue through the morning. The density at Hermit Lake this morning was 8% and had accumulated 3.7” (9cm) by 6:30am. This was similar to field observations with fist (F) hardness in all places. Even with light winds by Mount Washington standards, soft wind slabs are forming as well as deeper drifts behind terrain features. These are the pockets that have the potential to entrain more snow and create probelms. Beware of deeper pockets of snow forming in the convex slopes below the steepest terrain and beneath ice climbs.

The Lion Head Winter Route is open and the most direct route to the summit from the east side of the mountain. Please be on the lookout for machine traffic on the Sherburne.

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 8:30a.m., Wednesday, January 18, 2017. A new advisory will be issued tomorrow.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2713

2017-01-18