Avalanche Advisory for Tuesday, February 7, 2017

Huntington Ravine has HIGH and CONSIDERABLE avalanche danger today. Central, Pinnacle, Odell, South, and Escape Hatch have High avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. North, Damnation and Yale Gully have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential.

Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger today. Left Gully and Hillman’s Highway have High avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. Lobster Claw, Right Gully, Sluice, Lip, Center Bowl, Chute, and Lower Snowfields have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential. Little Headwall has Low avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. Evaluate snow and terrain carefully and identify features of concern.

AVALANCHE PROBLEM: Today, Wind Slab will form. Avalanche danger will increase as the day progresses. Accumulating snow today (up to six inches during the daylight hours today and up to another six inches tonight) along with shifting winds that will increase are obvious red flags. With winds currently shifting to the SE, the most avalanche prone slopes this morning include:  Left Gully, Hillman’s Highway and Central through Escape Hatch. As winds shift to the W during the afternoon and snowfall continues, all forecast areas will see significant loading. By nightfall, some areas rated Considerable will be pushing the upper end of that rating and when this advisory expires at midnight, all forecast areas will likely be into a High rating.

WEATHER: Strong winds from the W and WNW started Sunday and continued through Monday. Light snowfall started Monday at 4pm and has not stopped. The rate of snowfall should pick up through the morning, bringing up to 6” by nightfall. Winds are currently from the W at 39mph on the Summit and should be shifting to the S by mid-morning, and then wrapping to the SE around noon while beginning to pick up in speed. Tonight, winds will shift back to the W by midnight and with continued snowfall, we may see another 6” by Wednesday morning. A band of warm air may mix in tonight for a brief period of freezing rain.

SNOWPACK: Strong winds over the past several days sculpted our snowpack into various firm surfaces. While some old surface was exposed, most areas were covered with a one-finger (1F) wind slab. Continuous upslope snow allowed for some softer pockets of snow to form, but these are in constant flux due to winds. Today, expect widespread upside-down wind slab to form due to accumulating snowfall and increasing and shifting winds. If traveling into avalanche terrain today, keep in mind that accessing any terrain may require traveling underneath forecast zones where natural avalanches are likely today. With large snowfields connecting our forecast zones and avalanches likely overnight, we may see the runout of both Huntington and Tuckerman avalanche paths pass their current season maximum.

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  8:30 a.m., Tuesday, February 7, 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

2017-02-07