Avalanche Advisory for Saturday 2-16-2013

This advisory expires at 12:00 midnight, February 16, 2013

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Lobster Claw, Right Gully, Left Gully, Hillman’s Highway, the Lower Snowfields, and the Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine has MODERATE and LOW avalanche danger. Central and Odell gullies have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas in Huntington have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Whether you’re here for just today or for the long holiday weekend, today looks to be the best day to get out and play on Mt. Washington. Temperatures will be seasonable, winds will be on the light side, and there is a chance that clouds on and above the summit will be breaking up. We got a dusting of new snow early this morning, but it’s not enough to increase the avalanche hazard. The stability problems we are currently monitoring are left over from two days of light snowfall on Monday and Tuesday totaling about 5″, which fell with strong SW winds Monday then strong NW winds on Tuesday. Through the course of the past week, we’ve been able to lower the danger ratings in a number of locations. Today, Pinnacle is the only additional area moving from Moderate to Low. The other areas that remain posted at Moderate will continue to trend in a similar direction, but we don’t have the confidence needed to drop them a full rating.

What you’ll find in many areas, particularly those posted at Moderate, is fairly deep wind transported snow. Layers of softer, weaker snow, and pools of graupel in some places, are lying underneath slabs that are more firm than what is below. We’ve seen clean shears at a lot of the interfaces between the various layers, but overall the snowpack is lacking “snap.” The technical way to say this is that there is limited potential for fracture propagation, but I like to think of it in terms of made-up words like snappiness. While the overall snowpack has limited snapiness, in some locations this property exists sufficiently for a person to trigger an avalanche. Examples include weak points in snow near buried rocks or ice bulges, shallower snow on top of water ice or rain crust, and more open steep slopes such as under the Lip in Tuckerman. Avalanche runout paths are not at all forgiving right now, most are filled with rocks, ice chunks, trees, etc., so the consequences of being involved in even a small slide could be dire.

It’s a holiday weekend, which typically means a lot of people on the mountain. While you and your group may be making good choices, don’t expect everyone out there to be knowledgeable about avalanches. Where you see tracks does not necessarily equate to prudent decisions! Pay attention to who may be above and below you, and whenever possible avoid traveling in the runouts of avalanche paths. The full fury of winter on Mt. Washington will be on display tomorrow and Monday. You’d be wise to get an early start Sunday and move quickly, because conditions will worsen through the day.

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 8:10a.m., February 16, 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

2013-02-16 Print Friendly