Avalanche Advisory for Tuesday 2-26-2013

This advisory expires at 12:00 midnight, February 26, 2013.

Tuckerman Ravine has Moderate and Low avalanche danger. Lobster Claw, Right Gully, the Sluice, the Lip, the Center Bowl, and the Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. 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 Gully has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow in isolated terrain features.

This has been an unusual stretch of weather for Mt. Washington. Average wind speeds on the summit have been around 20-25mph (30-40kph) each of the last 4 days. Today is no different; light winds and relatively warm temperatures will continue to allow for comfortable alpine recreation. With over 60″ on the summit so far and another storm arriving tomorrow, February has been a good month for snow, though the overall lack of snow leading into the month means a couple things. One is that many avalanche paths are only now developing to their “regular” size. Another is that many of the climbs in Huntington have very thin conditions near the top outs.  Also, getting out of the bowl is either an adventurous bushwhack to get to a thinly covered Little Headwall, or a hike down the trail.

We’re posting Moderate avalanche danger in many areas today. This means that you might trigger an avalanche in these locations. Some areas are at the lower end of the rating, while others are more in the middle of the rating range. The concerns stem from the most recent snow we received on Saturday and Sunday. NNW winds picked up on Sunday night and relocated this new snow around the mountain. The area I’d be most concerned with in Tuckerman is the Sluice, Lip, and Center Bowl; in Huntington this honor goes to Central Gully. These locations have the largest snowfields, are easily wind-loaded, and are some of the most frequent producers of avalanche activity. Old fracture lines in these areas have been reloaded, indicating the existence of windslab on top of old bed surfaces. We expected to see greater instabilities yesterday in Lobster Claw and Right Gully. In our trip to the top of Right we found a lot of hard old snow through much of the gully without a lot of loading, but there were stability concerns in the steep top section. Lobster Claw will have a similar issue as Right, so I’d say these qualify as being on the lower end of Moderate.

Left Gully also is dominated by older wind-affected snow through much of the route. However, the top climbers left side does fit the description of a pocket, or an “isolated terrain feature,” so you should approach this snow carefully and assess it as you go. Most of the gully has very good stability, hence the Low rating. Other areas in Huntington might have similar pockets in these isolated terrain features, so you should be watchful for signs of unstable snow as you travel. The top left side of South Gully is one example. The tops of Yale and Damnation did fill in with snow, but remember that before last weekend the tops of these were exposed rock and turf.

 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 8:15a.m., February 26, 2013. A new advisory will be issued tomorrow.

Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forests
(603) 466-2713 TTY (603) 466-2856

2013-02-26 Printable