Avalanche Advisory for Tuesday, February 17, 2015

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. Lobster Claw, Right Gully, the Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Left Gully, Hillman’s Highway, the Lower Snowfields, and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely. However, unstable snow may exist in isolated terrain features.

All forecast areas of Huntington Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely. However, unstable snow may exist in isolated terrain features.

AVALANCHE PROBLEM: Wind slab leftover from recent strong winds is the avalanche problem you’ll need to watch out for today. This can be found in isolated locations within forecast areas rated Low (e.g. the very top of Yale Gully) or in more widespread distribution in the Moderate-rated areas in Tuckerman. Slabs will have a lot of strength, which could lead you into a feeling of good stability, but if you should find a weak spot or tickle the weak layer in just the right way, you could produce a sizeable and destructive avalanche.

WEATHER: Compared to the last couple days, today will be a very pleasant day on the mountain. Light winds and temperatures above 0F are to be expected. There will be increasing cloudiness during the day as well, with a chance for some very light snowfall.

SNOWPACK: I’ll start with the easier discussion…Huntington Ravine has been pounded by very strong winds over the last two days. The surfaces there will be very firm and textured. As for avalanche concerns, there may be lingering pockets of instability. One that caught my eye this morning was the hangfire above a crown line at the very top of Yale Gully. You would be challenged to exit that route without climbing up over the crown and into the hangfire. In Tuckerman, Hillman’s and Left Gully have similar conditions as most of Huntington. As another example of how punishing these winds were, Dodge’s Drop (with a windward aspect) has eroded sufficiently that it is no longer continuously skiable snow. Be wary of any hard surface that sits on top of softer, weaker snow.

Elsewhere in Tuckerman, leeward aspects had windblown snow throughout much of the past two days. Yesterday morning, a thick slab released from the Sluice, but the Lip and Center Bowl showed no sign of recent avalanche activity. This tells me that these areas, and probably parts of Lobster Claw, Right Gully, and the Chute, stand a good chance at having unstable snow. It’s hard to ignore the bulls-eye data of recent avalanche activity on adjacent slopes as a sign of instability. Again, you should anticipate hard strong slabs but be on the lookout for any potential weaknesses, such as a thin spot toward an edge or locations near buried rocks or bushes.

I’d like to express my deepest sympathy for the family and friends of the hiker who perished while attempting to traverse the Presidential Range on Sunday. It’s important for us to remember that with adventure comes inherent risks, and we can never fully remove or mitigate the risk. This is true for seemingly benign trips as much as it is true for those where the risks are more obvious and apparent. I would like to encourage everyone who travels into the mountains to use this incident as a catalyst for self-reflection, rather than assigning fault, finding errors, or questioning judgment. We all have pushed our limits at one time or another. This is a case where one person’s choice for adventure had a very tight margin of safety, and due to circumstances that no one will ever fully know, she paid the ultimate price. For that, I am truly saddened.

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 8:25 a.m. February 17, 2015. A new advisory will be issued tomorrow.

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

2015-02-17