| Posted: 7:41 a.m., Monday, January 22, 2007 |
Huntington Ravine currently has Low avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely except in isolated pockets. Normal caution is advised.
Today's stability ratings remain the same as yesterday's with the main concerns still being in the Lip area and in the Sluice. In Huntington Ravine you will find most areas have been scoured down to old surface by high winds leaving very few areas of concern. In Tuckerman Ravine we found the usual spatial variability as we examined one area to the next. From Left Gully over to the Center Headwall I found a variety of hard slabs sitting over an icy bed surface. Hopefully that grabbed your attention. The Low rating in these areas is a result of the amazing tensile strength these slabs have as a result of being pounded by strong winds for a couple of days. The high density of these slabs made for ideal crampon conditions. I found it challenging to kick my double boot into the surface of them. I was also able to conclude that avalanche activity had occurred in Left Gully and the Chute. These probably happened during the day on Saturday while the ravine was being wind loaded. While the evidence wasn't as clear below the Center Headwall and Lip, I would feel comfortable saying something let go in these locations as well. The snowpack around the Lip, Sluice and in pockets of Right Gully contains areas of hard slab, soft slabs and some loose snow. These are the areas where human triggered avalanches are more of a concern particularly in the softer slabs. Realize that as you move from one location to the next your ability to trigger something changes as well. Chris found some very interesting weak layers in these locations that were composed of large rimed crystals and a lot of ice pellets that fell last Tuesday. We think the high winds over the weekend ripped up the rain crust and transported these ice pellets into the Ravine. They can be seen in the slabs themselves and in the weak layer simulating ball bearings. In conclusion, don't rely on one pit to make assumptions about the snowpack around you. Always keep your mind open to changing conditions and adjust your plans accordingly.
Speaking of changing conditions, it is currently snowing on the mountain. Snow showers are expected today and over the next couple of days. Today's expected accumulations are only .5 to 1" (1.2 to 2.5 cm) but it is always worth watching the weather and evaluating how the new snow may be affecting stability. This will become more important if we are fortunate enough to receive more snow than forecasted. Relatively light westerly winds on the summit will promote the development of soft slabs, particularly at the tops of gullies.
The Lion Head Summer Trail is still open. The Summer Trail crosses an avalanche prone slope that has not developed as of yet. The Winter Route is not built for travel without adequate snow cover, so although we are in winter, please help keep the Winter Route in good shape by using the Summer Trail.
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Avalanche Advisory Archives.
United States Avalanche Danger Descriptions.
Échelle Canadienne de risque d’avalanche.
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