Posted 8:15am, Friday, March 4, 2011
Tuckerman Ravine: Lobster Claw, Right Gully, the Sluice, Lip, Center Bowl, Chute, and the Lower Snowfields have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Left Gully, Hillman’s Highway, and the Little Headwall have Low avalanche danger. Natural and human-triggered avalanches are unlikely.
Huntington Ravine: All forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely.
Tuckerman Ravine this morning has an incredibly peaceful look to it. A smooth and uniform blanket of white canvasses much of the Center Bowl, Lip, Sluice, and upper portions of Right Gully and Lobster Claw. Winds are relatively calm and the skies are blue as a New England sky ever gets. Unfortunately, this will all change as a warm March weather system is nudging its way toward us for the weekend. For now though, as beautiful and inviting as it looks, there is avalanche potential lurking in the multitude of layers making up the upper portions of the snowpack. A quick field trip yesterday found an impressive array of layering within the upper 1+ meter of snow. These were undetectable to me by simply looking at and poking into the pit profiles. The various layers began to show themselves as I started doing stability tests, and by the end when I was jumping on the uphill sides to fill in the holes I was seeing upwards of a dozen different layers, a few of which would give me concern if people weren’t giving the slopes the respect they deserve. Carefully following rules of safe travel will be critical today, such as one at a time on a slope and treading lightly so your impact doesn’t penetrate too deeply. In Tuckerman today, the areas where newly developed slabs have the greatest potential for a person to trigger them are in mid-elevation of the Sluice, majority of the Lip and Center Bowl, and above the narrows of the Chute. Other areas might be on the lower end of the Moderate rating, such as Right Gully and Lobster Claw, but it would not be a big surprise to see a person hit the weak spot in just the right way to trigger an avalanche. On the other hand, it also wouldn’t surprise me to see people travel through here without incident. Before you go, think about how much you’re willing to risk; think about your ability to accurately assess the snowpack; think about your potential runout and your partners’ ability to find you, dig you out, and perform first aid if necessary…these certainly aren’t all the things you need to think, but it’s a good start before heading into avalanche terrain. The possibility of human triggered avalanches exists in many areas, so make informed decisions.
We do have several areas posted at Low danger today. This is thanks to the strong winds that ripped through the mountain on Wednesday night. In Tuckerman, Left Gully and Hillman’s Highway, as well as just about all of Huntington Ravine, have a lot of wind effected snow. This snow will be quite strong and hard and have a rippled texture. Not the best skiing, but a much different level of avalanche danger than in Moderate-rated areas. Other areas of Tuckerman also have sections that have been heavily wind effected. One example is the very top of the Chute, but to get there you’ll need to pass through a large pillow of slab sitting just above the narrows.
It looks as though the weekend weather system is going to be a slow-moving mess. Snow may start on the mountain as early as Friday night but by Sunday it will have turned over to a wintry mix, at best. There is a chance it will be rain all the way to the summit. Warm temperatures will persist into Monday! As we do each Friday afternoon, we’ll post our thoughts about the upcoming weekend to the Weekend Update section of our website. Expect this weather system to have an effect on snow stability.
- 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