Avalanche Advisory for Tuesday, March 8, 2016

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. The Sluice, Lip, Center Bowl, and Chute have Considerable avalanche danger. Dangerous avalanche conditions exist. Natural avalanches are possible and human-triggered avalanches are likely. Lobster Claw, Right Gully, Left Gully, and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. The Lower Snowfields and Little Headwall are not posted due to a lack of snow in these areas.

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

AVALANCHE PROBLEM: Today will be a head’s up day in avalanche terrain, so pay attention. Wind slabs that developed as a result of yesterday’s 2″ (5cm) storm are the primary threat. These slabs will be warming today along with ample sunshine on south and east aspects. As temperatures rise, expect decreasing stability. However, even in the colder temperatures starting today I’d be very cautious treading into any location with fresh wind slabs. The areas of greatest concern include the Sluice, Lip, and Center Bowl in Tuckerman and Central, Odell, and South gullies in Huntington.

Your best bet is to play it safe. Avoid the big slopes at the height of the day. Stability will be changing throughout the day – DO NOT ASSUME THAT TRACKS ON A SLOPE ARE AN INDICATOR OF STABILITY.  I expect there may be some people out there pushing the envelope. Don’t be fooled into thinking they were doing so in a wise or safe manner. Some do, but in Tucks in March, I’d say that most allow their desires to overtake their sensibilities.

WEATHER: This morning’s weather is very inviting…clear skies, calm winds (35-50mph on the summit), and warming temperatures. Couple this with smooth slopes with more snow coverage than they’ve had all year and my hackles go up about human-triggered avalanches. The weather today will contribute to a period of worsening stability as temperatures rise above freezing. Summit temps are expected to go into the 30’s F, so ravine temperatures will likely be well above freezing soon.

Snow fell yesterday morning and afternoon, bringing about 2″ of 14-15% density snow to elevations from Hermit Lake to the summit. It began with winds from the SW in the 55-70mph range, though they shifted to the W during the snowfall and then from the WNW around 50-60mph in the hours of wind loading after snowfall had ended.

SNOWPACK: Things are still pretty thin and bony, but we have better all around snow coverage right now than we’ve had all season. Yesterday’s loading put fresh slabs in most locations, causing our avalanche concerns to rise. We have not yet had a good look at Lobster Claw or Right Gully to see how much new slab is in there. If today were to be a typical cold winter day, we would be sitting solidly in the Moderate range for new slab instabilities. All areas, especially the Lip through the Chute, have new slabs that should give you concerns while you drool at them from afar. As these slabs developed in cold temperatures yesterday, today will be the first time they’ve gone above freezing. This tends to destabilize snow for a period of time, but eventually it might have a beneficial affect on the stability. I could envision a scenario where conditions are fairly stable at some point later today, but there is no way to predict at what point this might happen.

Secondary to new slab instabilities, there are older slabs and hangfire from the last storm. This will add some complexity to your terrain management and snowpack evaluations. Don’t just look at the surface snow, think about what’s below and the consequences of triggering a larger avalanche.

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 8:35a.m., March 8, 2016. 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

2016-03-08