Posted 7:45a.m., Wednesday, February 09, 2011
Tuckerman Ravine has Considerable avalanche danger today. Natural avalanches are possible and human triggered avalanches are likely. The Lower Snowfields have Moderate avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. The Little Headwall has Low avalanche danger. Natural and human triggered avalanches are unlikely in this forecast area.
Huntington Ravines has Moderate avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible.
Howling winds are pummeling the mountain this morning as they have been since early last night. Snow fell through most of the daylight hours yesterday but winds ramped up to 90+mph (145+kph) by midnight and trying to ascertain a snowfall total is near impossible. From what we saw firsthand I would guess that we picked up 3-4 inches of medium density snow. In addition to what fell in the last 24 hours the winds have also been able to tear into the older snow. The crust formed by last weekend’s mixed precip event helped shield some of the snow from Monday’s winds which were strong but not as strong as they are right now. As speeds pushed higher than they have in the last week, snow that was once protected was torn up and redeposited far from home. With this in mind the wind transport and loading that continues to occur is probably similar to a 6-8” (15-20cm) storm. Visibility is nonexistent right now so it’s impossible to say exactly where all of this snow ended up. I can guarantee that much of it was moved down into the woods where trees provide good wind protection. Other sheltered locations that likely held onto snow are any protected areas with E to SE aspects. With this in mind the area of most concern in Tuckerman today is the Chute through the Sluice. In Huntington it would be O’Dell through Yale. Historically, similar wind speeds have scoured most areas in Huntington and pummeled the snow in the top of Tuckerman’s Left Gully. This may very well be the case today but with no visibility we can’t know for sure. Each day and weather event is unique and we’re often amazed how different the ravines can react to similar conditions. Saturday’s mixed precip event not only created a crust in most areas of the mountain but it also dumped a wide variety of precip forms including cold snow, graupel, and ice pellets that were the size of small peas. Each of these forms reacts differently to winds and contact with other layers. As a result the spatial variability was high immediately after the storm and these recent winds and any resulting avalanche activity has increased the variety of conditions found in our forecast areas. If you choose to travel in avalanche terrain today you’ll need to pay close attention to changes in stability as you move over short distances.
- 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.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856