Posted 7:45 am, Saturday, March 26, 2011
Tuckerman Ravine: Sluice, Lip, Center Bowl and Chute have HIGH avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Travel in avalanche terrain is not recommended. All other forecast areas in Tuckerman Ravine, with the exception of the Little Headwall, have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. The Little Headwall has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.
Huntington Ravine: All forecast areas in Huntington Ravine have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely.
Winter’s talons are keeping a firm grip on the mountain this weekend. Numerous avalanche issues, strong winds and temperatures struggling to reach 0F (-18C) on the summits will make you forget that we celebrated the first day of spring last week. Today is a heads up day for anyone venturing into avalanche terrain. The mountain picked up a surprise 11.8″ (30 cm) of new snow over the past two days and W and NW winds have been transporting it into the ravines resulting in natural avalanche activity. The new snow density is light, around 5%, and it has proven to work effectively with the wind to create very reactive wind slabs. While visibility was limited yesterday, we were able to see some impressive crown lines from recent avalanches, including in terrain that doesn’t usually avalanche. While additional snowfall will be limited today, we are expecting a notable increase in winds. They will remain out of the NW and climb into the 55 to 75 mph (88 to 120 kph) range with higher gusts. These will be the strongest winds the new snow will have endured so we expect significant wind loading to continue today. Natural avalanche activity remains a significant issue. You may notice that we dropped many areas down to Considerable from High. This is because we think peak instability has passed; however, we think the definition of Considerable reflects our expectations of the snowpack very well: Natural avalanches are possible and human triggered avalanches are likely. We left some areas in Tuckerman Ravine at High because we think it is likely that these forecast areas will continue to avalanche when the winds increase. One thing to keep in mind is that we could have some pretty substantial avalanches today, including in areas rated at Considerable. Walking into the base of either Ravine will put you in the run-out of multiple paths.
The Lion Head Winter route is filling in and avalanche terrain exists around this route. Chris marked the best route with bamboo poles yesterday. Stay on this path to avoid the more significant avalanche terrain on either side. If you were hoping for a mellow saunter up to the summit, you better plan your trip for another day. Today’s conditions will test your winter mountaineering skills due to poor visibility, strong winds and cold temperatures. This stretch of weather will continue tomorrow with slightly higher winds and similar temperatures. While some areas may come down a rating tomorrow, expect similar avalanche problems to persist. Cold temperatures won’t allow for much settlement in the new snow.
- 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.
Brian Johnston, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856