Posted 9:23a.m., Friday December 24, 2010
Tuckerman and Huntington Ravines have both LOW and MODERATE avalanche danger today. Natural and human triggered avalanches are unlikely in areas posted at Low and natural avalanches are unlikely and human triggered avalanches are possible for areas posted Moderate. We have not begun forecasting for the Escape Hatch, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas. Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.
Tuckerman: Hillman’s Highway, Left Gully, Chute, and Center Bowl have Low avalanche danger. The Lip, Sluice, Right Gully, and the Lobster Claw have Moderate avalanche danger.
Huntington: South, Odell, Pinnacle, and Central have Low avalanche danger. Yale, Damnation and North have Moderate avalanche danger.
After a number of days of cloudy upslope snow conditions we finally have a beautiful morning on Mount Washington with outstanding visibility. Yesterday’s projected wind speeds fell quite short of expectations and therefore we have a different snow stability situation today than I was anticipating yesterday. Winds were forecasted to gust to 80 mph, but only reached a peak velocity of 54 mph. This is still a respectable speed but had the forecast come to fruition we believe a lot of snow that had been sitting above treeline had the potential to scour off and load into the Ravines. With all that said our nickel and diming precipitation accumulations are adding up and snowfields continue to grow. Over the past 4 days the summit received 11” (28cm) of snow with moderate northerly winds. Occasionally wind direction vacillated a bit but most loading came in from pretty close to true N. This has left a number of south facing aspects less wind effected and loaded with more new slab than many other aspects that were either wind packed or scoured in most instances. A number of areas forecasted at Low have stability issues just below what I would consider the appropriate criteria to be listed at Moderate. Although they are posted at Low realize they aren’t the rock solid no-brainer we can see with very high winds or very cold temps after a rain event. As discussed yesterday anchors and the broken nature of many snowfields are assisting some slabs to remain in place, but as you move through a patchwork of snow, bushes, rock and ice re-evaluate slab stability constantly. Due to the spatial variability across areas like the Center Bowl in Tuckerman expect changes in slab quality and strength. Slopes with southern aspects like the climbers right side of the Lip, the Sluice, Right Gully, Lobster Claw, Yale and Damnation and North have softer slabs in the strong lee protected from N winds than areas posted at Low. We will spend some time in the field this morning taking a closer look at some of our problem areas and discuss anything we find in the Christmas advisory. We will start the Weekend Updater next Friday which will occur each week through May 2011. Have a great Holiday Weekend and if you’re still desperate looking for the perfect gift for your mountain obsessed love one order up an avalanche beacon and throw in an airbag for good measure.
- 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.
Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856