Avalanche Advisory for Tuesday, 1-29-2013

Expires at 12:00 midnight 1-29-2013.

Tuckerman Ravine currently has Moderate and Low avalanche danger.  The Lip has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The rest of the forecast areas in Tuckerman Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine currently has Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.

Let’s cut to the chase today…snow stability during the daylight hours will be generally good, with some areas of concern. After dark, winds will begin to increase. This will cause the avalanche danger to begin rising, so if you’re out late today, expect avalanche danger to exceed the currently forecasted ratings.

Yesterday a light blanket of snow fell with rapidly diminishing wind speeds. This weather system left behind about 3-4″ of 6% density snow at elevations from Pinkham to Hermit Lake, while the summit is reporting 5.4″. Currently this snow isn’t doing anything to change the avalanche danger. It’s just sitting on top of whatever was there yesterday. Most of the prior snow surface was stable, wind-rippled, and fairly hard. Some locations had been scoured to expose an icy crust. Stability concerns could be found yesterday in strongly wind-protected areas such as the Lip and other isolated terrain features. These are the same places where we have concerns for the better part of today. If you are attracted to smooth and creamy features, be aware that the beauty may only be skin deep. Underneath you may find a temperamental snowpack waiting for just the right trigger to come along. Don’t be lured by superficial beauty; quality time can be spent in some of the less attractive areas and this is more likely to be a more stable relationship.

Moving into tonight, SW winds will begin to increase. The trend will continue through Wednesday with gusts reaching over 100mph (162kph). This will pick up snow from where it sits in the alpine zone, and load it into slabs on top of the existing light density blanket. It’s a pretty good set up for increasing avalanche danger, particularly on aspects facing to the north and east. The areas that will be slowest in developing stability problems will be the northern gullies of Huntington and Lobster Claw and Right Gully in Tuckerman. As if the snow and wind weren’t doing enough to create avalanche problems, tonight and tomorrow temperatures will steadily rise and we will be seeing some mixed precipitation and rain. The heaviest rainfall isn’t forecasted until Wednesday night, but even prior to this, the onset of sleet and rain will quickly exacerbate any of the newly developed avalanche problems.

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 8:20a.m. January 29, 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

2013-01-29 Print friendly

Not yet the weekend, but an update

With incoming warm weather, mixed precipitation, and rain, we wanted to get a better handle on how the snowpack would react in coming days. This was a small part of our field work today.

Remember, Tuckerman has a strong degree of spatial variability for much of the winter. This quick pit was dug in a location where the snow underfoot changed, causing us to stop and take a closer look. What we found here is similar to other areas, though the most noticeable difference is the hard slab layer is slightly thinner than much of the rest of the Center Bowl.

Remember to continually assess conditions and be alert to changes as you move through the terrain.

For record, this stability tests in this pit gave us scores of CT30, Q3 and STH, Q3. Stability was good in this location at this time. The avalanche danger rating for the area was Low.