Posted 8:46a.m., Tuesday, December 28, 2010
Tuckerman Ravine has High and Considerable avalanche danger. Huntington Ravine has Considerable avalanche danger. The Sluice, Lip, Center Bowl and Chute have High avalanche danger. In these areas natural avalanches are likely and human-triggered avalanches are very likely. Travel in avalanche terrain is not recommended. All other forecast areas have Considerable avalanche danger. Natural avalanches are possible in these areas and human-triggered avalanches are likely. We have not begun forecasting for the Little Headwall, Lower Snowfields or Escape Hatch due to a general lack of snow. Forecasting will begin in these areas when conditions warrant although avalanche activity may occur prior to this point.
Things are happening on Mt Washington! Our trip up the trail this morning included chainsaw work for fallen trees that had been snapped by strong winds. We also observed heavy drifting along the trail while other areas were scoured down to old surface. These clues provide insight into what may be happening behind the clouds of blowing snow that conceal both ravines. As a quick recap we picked up more snow than was expected from the Nor’easter but strong winds made exact measurements impossible. Between measurements at our snow plots, along the trails and down at Pinkham it appears that we received somewhere around 18” (45cm) of 8-10% snow. The Observatory recorded less than that but it’s difficult to determine how accurate their measurements were in the hurricane force winds. Reports from around the White Mountain region confirm high variability in snowfall amounts from a 5″ (13cm) in the Conway area to more than two feet (60cm) in Randolph and Crawford Notch. Winds throughout the snow event have been in excess of 50mph (81kph) with recent observations at the summit pushing toward today’s forecasted speeds of 100mph (161kph). The winds initially blew out of the NE but later swung through the N during yesterday’s snowfall before ending up in the NW where they are expected to stay through tomorrow. This drift across the compass allowed all areas to pick up wind-transported snow through direct and cross-loading activity. Avalanche activity and high winds have likely cleaned new snow out of some areas and restarted their loading cycle multiple times. Poor visibility is preventing us from getting much visual data from the ravines and blowing snow will likely continue to problem through the day. Nonetheless, the Observatory is continuing to report blowing snow and increasing winds will keep moving the snow from the NW side of the mountain up and over to Tuckerman and Huntington ravines.
Arctic cold continues to dominate the weather pattern today with a current temperature on the summit of -8F(-22C). With winds pushing 100 mph and snow to fill the air, a trip above treeline today is asking for trouble. Yesterday we had an incident with a hypothermic patient at Hermit Lake. The weather is nasty out there and you’ll need to bring lots of extra equipment to ensure a proper margin of safety. It should be assumed that all trails except for the Tucks Trail are unbroken and heavily drifted. Snowshoes or skis will be necessary to navigate off of any packed trail.
- 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.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856