Posted 8:15a.m., Wednesday, March 23, 2011
Tuckerman Ravine: The Sluice, Lip, Center Bowl and Chute have CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. All other forecast areas in Tuckerman Ravine 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: Central Gully has CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. All other forecast areas in Huntington Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.
Heads up out there today! Don’t let the blue skies and calm winds lull you into thinking the snow is stable. In the past two days, the Summit has received 6.1″ (15.5 cm) of new snow. This was accompanied by winds that started from the south, then shifted to the SW, W and NW. Yesterday’s average wind speed up top was 38 mph (61 kph) with a peak gust out of the NW at 60 mph (97 kph). These winds are not strong by our standards and looking around the mountain today we see a lot of smooth wind slab. The Lip has a faint hint of a recent fracture line and a jagged fracture line can be seen in the top of the Duchess. Recent wind deposited snow is hiding any other evidence of recent avalanche activity. Today’s winds will be shifting to the W and decreasing though the day. This will make natural avalanche activity less likely but we are quite concerned about the ability of new soft slab to withstand the stress people could put on them. The new wind slabs are sitting on a hard and icy bed surface and I don’t expect slab hardness to promote stability. In other words, if you travel in avalanche terrain today, I think you could trigger an avalanche. Good route finding and snow stability skills may open some opportunities; however, most forecast areas don’t have options that avoid new wind slab. If you play it safe, you can still have plenty of fun today. The Sherburne Ski Trail is in great shape, the Little Headwall itself has reasonable snow stability and the Lion Head Winter Route will provide you an opportunity to get up above treeline without putting yourself at risk of avalanches.
Clouds will move in later this afternoon and there will be a chance of snow showers. A weak disturbance will provide the mountains an opportunity to pick up a trace to 2″ of snow tonight and another trace to 2″ tomorrow. Be sure to check tomorrow’s advisory to see how new snow may be effecting the avalanche danger.
- 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