Avalanche Advisory for Sunday, April 15, 2018

Huntington and Tuckerman Ravine have LOW avalanche danger. All forecast areas have Low avalanche danger. Generally safe avalanche conditions exist. The exception to this is the Little Headwall which is no longer rated due to a lack of snow and is not advised as a route of travel.

AVALANCHE PROBLEM: We are currently in the freeze portion of a prolonged melt-freeze cycle that began on Friday which is largely eliminating avalanche concerns for the day. With continued below freezing conditions today, long sliding falls will be much more of a hazard today. Crampons, an ice axe, and the ability to use them will make travel in avalanche terrain possible. Climbers should be aware of the potential for ice dams as the current freeze may trap flowing water. This trapped water will be looking for a pressure release valve in the form of an ice tool or screw placement. The thaw over the past two days has also reopened holes in the snow on the Little Headwall, making this no longer an advisable route to exit Tuckerman Ravine. Many skiers and riders were seen removing skis and boards and trying to down climb the combination of refrozen snow, ice, and verglassed rock. Hiking down the Tuckerman Ravine Trail to Hermit Lake will be both faster and safer at this point.

WEATHER: Just about every possible type of mixed precipitation fell onto Mount Washington yesterday. All told, we received 0.35” of water. This came largely as ice pellets, freezing rain, rain, and snow. Winds calmed from W at 45mph yesterday morning to a current N at 8mph this morning. Today, unsettled weather will continue, allowing the temperature to remain around the freezing mark with another 0.2” of liquid precipitation coming in various forms. The wind will wrap from the north through east to SE by early afternoon with speeds staying under 20mph until the evening. If conditions allow and we see all snow today, we could see up to 2”, though it seems more likely that sleet and freezing rain will mix in.

SNOWPACK: Prior to the warm-up on Friday, our snowpack of concern consisted of soft slab of variable thickness, up to 2’ in places, sitting on top of a decomposing melt-freeze crust. Due to warm temperatures and sunshine, this became a wet avalanche problem on Friday into Saturday morning. Earlier than expected on Saturday temperatures dropped and a refreeze began, slowly penetrating into the snowpack and locking things into place. With skier traffic in many areas Friday and Saturday as well as many large roller balls on Friday, the surface of this refrozen snowpack is ugly and likely to provide rough skiing.

The Sherburne saw heavy traffic yesterday from the Friends of Tuckerman Ravine Inferno Pentathlon. Expect large, frozen moguls with icy troughs in between. Some bare spots exist down low, but coverage is remarkably good.

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.
• Posted  7:30 a.m., Sunday, April 15, 2018. A new advisory will be issued tomorrow.

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

2018-04-15