Posted 8:40a.m., Friday, April 1, 2011
Tuckerman Ravine: Lobster Claw, Right Gully, the Sluice, Lip, Center Bowl, and the Chute have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Left Gully, Hillman’s Highway, and the Lower Snowfields have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Little Headwall has Low avalanche danger. Natural and human-triggered avalanches are unlikely.
Huntington Ravine: North, Damnation, Yale, Central, and Pinnacle gullies have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Odell, South, and the Escape Hatch have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.
Let’s set aside the nuances of today’s weather for just a moment and focus on the most important piece of information. A Winter Storm Warning is in effect until 10pm. The trend today is for INCREASING AVALANCHE DANGER THROUGHOUT THE DAY AND OVERNIGHT. We’re starting the day with good stability in most locations, but this will change as Mother Nature drops her load across most of New England. We’re expecting 5-7″ (13-18cm) during the day and 2-4″ (5-10cm) more overnight. With the temperatures we’re seeing up on Mt. Washington, we expect the snow to be lighter in density here than it will be down in the valleys. This will help allow the winds to pick up the fresh snow and transport it into the ravines. Today’s winds are forecasted to increase in speed through the day as they wrap around from the ESE, moving to the NE, and coming from the NNW by 8pm or so. As the shift happens, loading and cross-loading will begin to take place on top of the thin blanket of new snow that’s already fallen. Into the night the increasing trend will continue. Most areas will push into the upper end of their ratings by the end of the day and will surpass today’s ratings at some point in the night.
Today’s stability issues will be most prominent and develop most quickly on S-facing slopes such as North and Damnation Gullies in Huntington and Lobster Claw and Right Gully in Tuckerman. However, expect significant cross-loading to occur on E aspects (e.g. the Center Bowl, Central Gully or Pinnacle) particularly late in the day when winds have shifted to a more northerly direction. Even relatively small E aspects may have unstable snow that could produce natural avalanches as the day progresses. Examples of this would include areas forecasted at Moderate today, such as the climbers’ right sides of Hillman’s, Left Gully, or South Gully. Although we believe this is unlikely to be the case until late today or into this evening, we aren’t ruling out the potential. Remember, the forecasted ratings are limiting in that they represent the avalanche danger in just one word. Today you will do well to pay attention to the big picture that is going on around you.
Expect tomorrow’s danger rating to be elevated, as winds will continue to shift towards the NW and remain fairly strong into tomorrow. This pattern is far more typical of winter weather than springtime, so if you’re thinking about spring skiing conditions you may want to look elsewhere tomorrow. We’ll update you tonight on the Weekend Update section of our website.
The best line up the Lion Head Winter Route at treeline is marked with bamboo poles. Evidence of recent avalanche activity can be found on both sides of the route. Shifting winds tonight will continue to fill in these steep snowfields. Stay on the marked path to avoid the more significant avalanche terrain on either side.
The Harvard Cabin will be closing for the season after Saturday night. Beginning April 3rd, the only place you may camp on the east side of Mt. Washington will be at Hermit Lake Shelters in Tuckerman Ravine.
- 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.
Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856