Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 7:53a.m., Tuesday, April 19, 2011

Tuckerman Ravine has Low avalanche danger.  Natural and human-triggered avalanches are unlikely but you’ll want to watch for unstable snow on isolated terrain features.

Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington Ravine. A danger of falling ice exists and will persist until it all comes down.

Monday is behind us and today looks like it could be a decent day on the mountain.  There are some thin high clouds but overall the weather is nice and I’m happy to see my shadow. A quick scan provides evidence of the recent snow that fell on the mountain.  In most places it is merely dust on crust but there are a handful of locations, especially protected E aspects, where it has piled up a little deeper.  The temperature has stayed cold enough that the new snow in the courtyard at Hermit Lake remains dry and has yet to be affected by the sun.  This should change today however as temperatures are expected to push the freezing mark in our forecast areas and winds should mellow out to 30mph (48kph) from the WNW.  Where a thin blanket of snow covers the old surface we’ll probably see a change to mush on top of an icy surface that is slow to soften.  Where the old surface is exposed to the sun we’ll see something more akin to springtime corn snow.  One of the biggest factors in the different reactions to solar gain between the two snow types is color and this will help you plan your route selection.  The older snow is dirtier and darker and stands in relatively stark contrast to the fresh-looking white stuff from the past couple of days.  While the lighter snow will reflect much of the sun the darker snow will absorb that heat which will in turn loosen some of the icy bonds that hold the large snow grains together.  Voila! A thin layer of spring corn for your recreational pleasure.  Where might one go to harvest such fruit of the mountain you ask?  I’d place my money on the south-facing slopes from Lobster Claw around to the Lip but watch the run-outs below some of these slopes.  The Lunch Rocks are slowly melting out and a sliding fall in a yet-to-be-softened Sluice or Right Gully has the ability to send you flying right into the first aid cache. Ironic but true. We still have a few more degrees until we push above freezing at Hermit Lake so don’t get too excited and run out there before the sun has worked its magic.  Patience young Grasshopper! 

You’ll also want to identify and avoid the waterfall hole in the Lip which has been partially obscured by new snow.  Inside this hole is a waterfall which feeds a river under the floor of the ravine.  Falling in there is bad, REALLY bad.  As you wrap farther around the compass rose and start dealing with E and N aspects less softening will occur and you’d be better off looking for new cold snow rather than softened old surface.  Just remember that this new snow overlies a very icy bed surface and isolated pockets of windslab could be reactive to a human trigger.  They may not be big enough to bury you but if they knock you off your feet and spit you out onto a 40 degree icy slope you’re probably going to be least happy person on the mountain.  Crampons and an ice ax will be the tools of choice while traveling over the rock-hard old surface until it softens and in shaded areas this is unlikely today.  Remember the groundhog parable—we can learn a lot from watching shadows.

The Sherburne Ski Trail is bumped up for your enjoyment.  When it is frozen it is hateful.  When it is soft it may make you smile.  Watch for water ice, vegetation and the occasional rock poking through the snow.  If your legs allow you can make turns all the way to the parking lot.

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 caretaker at Hermit Lake Shelters.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713  TTY (603) 466-2856

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