Posted 7:40a.m., Wednesday, April 27, 2011
All forecast areas of Tuckerman Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely.
Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington Ravine. A danger of falling ice exists and will persist until it all comes down.
Today looks to be somewhat similar to yesterday’s foul weather but with a few positive exceptions. Compared to yesterday’s 0.5” (1.3cm) of rain we can expect maybe 0.1” (3mm) to fall today unless a passing thunderstorms decides to park itself above the mountain for an extended period. Clouds will be ever-present but we may see some breaks later in the day that will tease us with conditions that unfortunately won’t settle in for long. Temperatures will rise as a warm front moves past and the summit is expected to reach the lower 50s F (10-11C). It’s been days since we had sustained freezing temps in the ravine and the Cutler River is busy sending much of the snowpack out to sea. Depending on the snowpack structure, sustained warming like this may have a negative impact on stability as bonds break down and water erodes between layers. Luckily our snowpack has benefitted from melt-freeze cycles earlier in the spring and warmth-induced avalanches are unlikely. Though settlement has occurred the snowstake at Hermit Lake has only lost 4.3” (11cm) over the past three days and we’re still at 56” (143cm).
Of all the hazards out there avalanches are not going to be your biggest concern today. Poor visibility may impact your ability to pick out the springtime hazards that have just begun to show up to our party. The waterfall hole to skier’s right of the Lip has grown with the increased flow rates of recent days. Do yourself and stay out of this area. It would eat you up but probably wouldn’t spit you out until the snow melts away. Other crevasses have opened up in the Headwall and Lip. While most won’t swallow you whole, you might punch through on your climb up or catch a ski on your way down. Give these more room than you may think is needed. Climb up what you plan to descend so that you can identify these hazards and make a plan for avoiding them instead of being surprised on the way down. Icefall is starting to become an issue with the recent melt as well. Currently the largest of the ice pieces appear to be holding on, but it’s only a matter of time before it all comes crashing down. Do your best not to be under it when that happens. If you do spend time below ice use a natural barrier like a boulder as a shield and formulate a plan before you hear the crash of a van sized chunk breaking loose. Undermined snow is a notable hazard you’ll face and you should be on high alert today. This is when the snow bridges are eroded away from below and weakened by warm weather. Collapsing through, whether into a stream bed, crevasses, or the dreaded waterfall hole itself, can have dire consequences. You’ll want to evaluate the thickness and strength of snow bridges carefully before trusting them to hold your weight. Walking from the Bowl down to Hermit Lake is a smarter idea then trying to ski across the last chunk of snow above the swollen river.
The bottoms of the hiking trail and the John Sherburne Ski Trail are melting out quickly. Currently the ski trail is still open all the way to Pinkham Notch. Moguls are abrupt and abundant, and the thin sections are transitioning to longer stretches of bare ground. We’ll be monitoring the rate of decay and start closing off the bottom sections of trail when it becomes necessary to protect the 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.
- 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