Avalanche Advisory for Saturday, 3-23-2013

This advisory expires at 12:00 midnight, March 23, 2013.

Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger today. Very dangerous avalanche conditions exist; travel in avalanche terrain is not recommended. Right Gully, the Sluice, Lip, Center Bowl, and Chute have HIGH avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Lobster Claw, Left Gully, Lower Snowfields and Hillman’s Highway have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. The Little Headwall has Low avalanche danger.

Huntington Ravine has HIGH and CONSIDERABLE avalanche danger. Central, Pinnacle, Odell, and South gullies have HIGH avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. All other forecast areas have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely.

It’s been a long time coming, but winter finally seems to have arrived in full force. Today will have conditions to rival the most rugged winter day. Near zero visibility, blowing and drifting snow, very strong winds, and cold temperatures will make it a good idea to stay lower on the mountain. Travel into the ravines and above treeline will be tough, and in the case of the ravines, carry the additional risk of large avalanches running farther downslope than they have yet this season. I do not recommend you go into the floor of Tuckerman or Huntington to “have a look” due to the risk of large avalanches today.

The last week has been eventful for snow lovers. We had a good storm on Tuesday followed by a windloading event on Wednesday that produced some good avalanches and left many slopes loaded with slabs. Since then, we’ve had over 6″ (15cm) of additional upslope accumulations, most of which came yesterday evening. Upslope snow showers continued through the night and will continue today, bringing another 2-4″ (5-10cm)during the day. From what we’re seeing on the ground, I wouldn’t be surprised if we exceed the forecasted total. This all adds up to a lot of snow being available for loading into avalanche paths. The wind will be the driving force that moves all this snow. Overnight NW winds increased in speeds, reaching a peak gust of over 100mph (160 kph) while writing this advisory. Expect all aspects and elevations to develop new windslabs. There is a chance that some areas, mostly those in Huntington, will be hammered into very strong hard slab by the strong winds, but this isn’t something I’d be willing to bet my life on. The differences between areas rated High and those rated Considerable are based on how they typically react to strong winds speeds as well as their previously existing slabs and bed surfaces.

Throughout today, I expect windloading to be significant in most areas of Tuckerman, likely producing multiple avalanches in the ravine, with some paths possibly running more than once. Due to the high wind speeds and new snow mixing with old redistributed snow, slabs that form today will be dense. These can build into large deep slabs that can cause a lot of destruction when they fail. We will wait this one out and only get up to see what happens after the avalanche cycle calms down a good bit.

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.
  • Posted 8:30 a.m. Saturday, March 23, 2013. 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

2013-03-23 Printable