Avalanche Advisory for Sunday, April 1, 2018

Huntington and Tuckerman Ravines have LOW avalanche danger. All forecast areas have Low avalanche danger. Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

 AVALANCHE PROBLEM: A significant melt/freeze event on Thursday and Friday generally resulted in refrozen hard snow in the ravines and minimizes concern for avalanche hazard today. If you’re venturing into the terrain today in hopes of spring skiing, you will likely struggle to find soft snow. Conditions will be better for climbers, with crampons, ice axe, and your ability to use them being necessary for travel on snow slopes today. Snow coverage has decreased slightly over the past week, with the Little Headwall transforming to an open stream bed and losing the most snow.

The firm conditions mean that long sliding falls are a key hazard to consider today. The recent warming also means that water is flowing beneath snow and ice. Undermined snow and weak snow bridges over this running water should be respected. Water running under ice can result in the “ice dam” effect, in which pressure builds from water flowing beneath. A tool, screw, or foot placement can rupture an ice dam in a potentially sudden and big way. Ice dams, undermined snow, and long sliding falls have all been the result of serious accidents over the years. Yesterday, a dog had a close call with fast moving water and undermined snow in the Little Headwall but was successfully rescued by people on site.

 WEATHER: Gusty winds from the SW blowing at a sustained 60 mph on the summit are ushering in a cold front. The warmest temperatures of yesterday and today are occurring this morning, with the summit in the mid-20’s F. Temperatures will drop steadily today and into tonight, with a low in the single digits on the summit. Wind is forecast to shift through W to NW and decrease slightly. A trace of snow is possible this morning, though no precipitation has been recorded yet from this weather system. Tomorrow will bring slightly warmer temperatures and much lower wind speeds. The currently cloudy skies should slowly give way to mostly sunny conditions by tomorrow afternoon.

SNOWPACK: The moisture and warming of late last week has been followed by a return to colder temperatures, mostly resulting in a refrozen upper snowpack. We did see enough softening on southerly aspects yesterday to allow decent turns, but shaded slopes remained hard. Cloudier skies and falling temperatures will make softening and corn snow skiing unlikely today. Conditions will be much better for ascending and descending with crampons and an ice axe. This first significant late season melt/freeze cycle may be the first of many that will transform our winter snowpack into the isothermal and relatively uniform snowpack characteristic of spring, but we’re not there yet. Layers of dry winter snow still exist beneath our hard refrozen surface snow. Continue to keep yourself informed as our snowpack continues to change.

 Check our Instagram page, linked on our website, for conditions photos and additional updates. You don’t need an account to view our posts!

 The Harvard Cabin is now closed for the season.

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 Harvard Cabin.
• Posted  8:00 a.m., Sunday, April 1, 2018. A new advisory will be issued tomorrow.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2858

2018-04-01