Avalanche Advisory for Monday, 3-12-2012

This advisory expires at midnight, Monday, 3-12-2012

 All forecast areas of Tuckerman Ravine and Huntington Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.

If this past weekend was marked by the arrival of spring, perhaps today could mark the arrival of summer? Not really, but my guess is that we’ll see at least a couple people hike up here in shorts and t-shirts today. Near-record high temperatures are in the forecast, with the ravine elevations of Mt. Washington already well above freezing and only getting warmer. Add to that some full sunshine, relatively calm winds, and a giant bowl-shaped reflector, and you’ve got some classic Tucks conditions. Bring your sunscreen, saxophone, wide-brimmed hat, or whatever makes you happy. If I were you, I’d bring my fattest sliding implements because it’s going to get pretty mushy by the end of the day, especially on S-facing aspects like Right Gully and the Sluice.

Overall snow stability around the ravines will be good today. The concern you’re most likely to face is loose wet sluffs on S and E aspects, i.e. those that get the most sun during the day. Elsewhere, there may be small pockets of slab on steep slopes that’s baking in the sun and haven’t yet seen traffic. These may release, but given their number, size, and isolated nature I don’t believe it’s enough to warrant more than a Low rating. Neither of these are to be taken lightly, as they can easily sweep you off your feet and carry you a long way downhill. Yesterday I alluded to potentially unstable slabs due to prolonged warming. The consensus among us is that it’s unlikely that today’s weather will be sufficient to overcome the stability created by the freezing-up following Thursday’s warm spell and rain. On that day, the summit was above freezing for about 14 hours and at the end of this period a shot of rain came through. This was the first warmth and water to impact the snowpack, but it didn’t trigger any avalanche activity. It quickly refroze on Friday, creating a strong crust layer that should be able to withstand today’s warm up before the threat of naturally triggered wet slabs arises again. The best we can hope for at this time are some cold nights, with temperatures below freezing, to start us on a good corn cycle. If we never go below freezing, we may start worrying again about natural wet avalanches. Let’s hope we don’t go there.

In Huntington Ravine, there is still ample ice in most of the gullies. However, there are some that are lacking a bit for this time of the year, notably the most northern gullies, North and Damnation. Expect the tops of these gullies to be a mix of ice, snow, rock, and turf. During the first hot days such as today, we often see numerous small rockfall events in Huntington, and occasionally some large ones. If you’re climbing in the sun, be very alert to what’s above you, whether it’s falling rocks, ice, or wet sluffs. Any and all of these can be expected today.

The Little Headwall has begun its annual deterioration. This winter it never really became an easy exit from the Bowl, so even though it’s only mid-March, it’s time to start thinking about walking out of the Bowl. There are open water holes in the stream above, and in the Little Headwall itself, so be cautious. The Sherburne Ski Trail is still holding up, but expect melting conditions down low.

Please remember:

  • 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.  
  • 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

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