Avalanche Advisory for Saturday, 1-4-2014

Expires at 12:00 midnight Saturday 1-4-2014

Tuckerman Ravine has Considerable and Low avalanche danger. Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely in these areas. Lobster Claw, Right Gully, the Lower Snowfields, and the Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.

All forecast areas of Huntington Ravine have Moderate avalanche danger. Heightened avalanche conditions exist on specific terrain features. Natural avalanches are unlikely and human triggered avalanches are possible.

AVALANCHE PROBLEM: Although it’s a clear blue sky, don’t be fooled into thinking the avalanche dragons have been put to rest until the next storm. A more appropriate way to think about today’s avalanche problem is that the dragons have camouflaged themselves and are in hiding, patiently waiting for a hiker, climber, or skier to come within striking distance. They won’t need much provocation today to become angry. Today’s issues are focused on human triggered avalanche activity.

Windslabs are the primary avalanche problem you’ll face today. These will be sensitive to triggering under the added weight of a person traveling through them. We believe the sensitivity of newly formed soft slabs in Tuckerman warrants a Considerable rating today, meaning that human triggered avalanches are likely. In Huntington, you’ll find a similar problem but on a less widespread scale, with more options for traveling around troublesome locations.

WEATHER: After a slight lull in the winds last night, velocities are ramping up again today into the 50-70mph (80-113kph) range with higher gusts. Temperatures will be rebounding from last night’s nosedive. The expected weather today might create a slow rise in avalanche hazard as increasing winds are able to find more snow to pick up and redistribute into the ravines.

SNOWPACK: In our forecaster’s discussion this morning, we had a discussion about whether the ratings should be Considerable or Moderate. The focus of this discussion was on just how probable it would be for a person to trigger an avalanche if one were to get onto a recently formed slab. We decided on Considerable in Tuckerman (meaning human triggered avalanches are likely) based on a handful of factors. These include: 1) very weak low density snow fell without much wind effect, followed by increasing wind speeds and harder slabs on top. This lead to numerous propagating cracks and collapsing snow in low angle terrain yesterday; 2) cold temperatures hindering any stabilization of the new slabs; 3) low drifting snow over the headwall has a history of increasing instability, sometimes producing naturally triggered avalanches in the Lip and Center Bowl; 4) increasing winds with stronger gusts possibly finding additional snow to load into the ravines; and 5) the ability of a person’s weight to penetrate a soft slab and overstress a weak layer below.

Huntington has many of the same issues, with all gullies holding some areas of concern. Near the tops you’ll find areas of soft slab that was protected from stronger winds. In some locations, the areas to be concerned with are located farther down the routes. While you may be able to avoid them, some places have wall-to-wall wind pillows. These should be treated with caution if you cannot avoid them.

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 0830 Saturday, January 4, 2014.  A new advisory will be issued tomorrow.

Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-285

2014-01-04 print friendly