Avalanche Advisory for Thursday, March 19, 2015

This advisory expires at midnight.

Tuckerman has Moderate and Low avalanche danger.  Lobster Claw, Right Gully, Sluice, Lip, Center Bowl, Chute and Lower Snowfields have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions on specific terrain features exist so evaluate snow conditions carefully to identify features of concern.  Left Gully, Hillmans Highway and the Little Headwall have Low avalanche danger. Natural and human-triggered avalanches are unlikely but watch for unstable snow on isolated terrain features.

Huntington Ravine has Low avalanche danger.  Natural and human triggered avalanches are unlikely except in isolated terrain.  These pockets of concern do exist is some locations.

AVALANCHE PROBLEM: Wind Slabs are the primary concern today.  Firm and stubborn wind slabs were built up during the last 36 hours of high wind. These slabs are largest in Moderate rated areas and most easily triggerable in the steepest or most wind protected areas of these gullies. Areas that fit this description are near the top out of Lobster Claw and Right Gully and in the Lower Snowfields at the convexities near the top of the “Christmas tree” feature and in the debris cone of Duchess. Sheltered areas near cliff walls and beneath steep pitches of ice may also harbor pockets of wind slab so stay alert in these areas as well. Larger areas of this wind slab in the Sluice, Lip and Center Bowl should have your hackles up due to the expansive nature of the slabs that exist there. Though stubborn, these areas hold the potential for larger and deeper avalanches.

WEATHER: Continued unseasonably bitter cold is on tap today with the NW wind finally diminishing a bit from the current 70-90 mph (115-145km/h) to the 50-70 mph (80-115 km/h) range later today. Since mid-day on Tuesday, gusts in excess of 100 mph (160 km/h) have been recorded 15 times in the past 36 hourly recordings with the period of highest peak wind speeds occurring from yesterday just after sun-up to around lunchtime. A cloud cap is still hanging around Tuckerman though Huntington is beginning to clear out. This clearing trend should continue through the day. The summit high temperature will reach all the way up to -5F (-20C) today after the mercury completes its downward journey to -20F (-29C) this morning.

SNOWPACK: It was pretty clear that our snowpack has taken a pummeling from winds as we bobbed and weaved between large wind drifts, downed branches and pine boughs this morning on the Tuckerman Ravine trail. A few brave souls made the journey up to ski the Sherburne trail yesterday with many resorting to goggles while skinning to deal with the wind and cold. Unfortunately, today won’t offer much better conditions. Old hard surface and wind hammered slabs would be your reward for pushing through the high wind and cold weather to reach our steep terrain. I suppose good cramponing with little post-holing puts a checkmark in the climber’s plus column, but tomorrow looks like a much kinder day for climbing as far as the wind and cold goes. An inch or three of new snow (2.5-7.5 cm) is possible starting tomorrow afternoon and overnight Friday.

There are little technical details to share as far as the snowpack goes. Hopefully we’ll be able to get into the terrain today to have a look at the current snow structure and determine if any forecast areas are more scoured than we think. If venturing above tree-line today, anticipate hard going with large snow drifts and high wind gusts to contend with. Though weather conditions are improving slightly through the day, climbing Mount Washington is still the real deal. Be prepared for arctic conditions despite the proximity of the vernal equinox.

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 8:05 a.m. March 18, 2015. A new advisory will be issued tomorrow.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2713

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