| Posted: 8:29 a.m., Sunday, February 24, 2008 |
Huntington Ravine has Low and Moderate avalanche danger today. North, Damnation and Yale Gullies have Low avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely except in isolated pockets. Normal caution is advised. All other forecast areas in Huntington Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Unstable slabs are possible in steep terrain. Use caution in steep terrain.
The overnight hours have displayed how subtle changes in weather can have significant effects on the snowpack. Yesterday's conditions were dominated by Low avalanche danger with some pockets of soft slab scattered around the Ravines that warranted caution. Overnight winds increased into the 30 and 40 mph range and moved the relatively small amount of light density snow that was available for transport into the Ravines creating new instabilities. These instabilities are more pronounced in Tuckerman and natural avalanche activity did occur overnight in the Headwall. The winds have since backed down and loading has subsided leaving us with a range of Moderate conditions. In Tuckerman, areas posted at Moderate are there right now with the Lip, Sluice and Headwall being at the upper end of the Moderate rating pushing Considerable. In Huntington, areas posted at Moderate are not there yet, however they do currently have pockets of wind slab. The most notable of these right now are in South Gully and Central Gully. All of the areas posted at Moderate in Huntington are forecasted to enter this rating with the increase in winds later and the associated slab development. Winds are expected to increase to around 50 mph (80 kph) out of the WNW between 3:00 and 4:00 this afternoon. This is something you need to be aware of and watch for today. Expect increasing avalanche danger with increasing winds due to new wind loading. In forecast areas that are posted Low today, you should expect to find isolated pockets of instabilities. Good route finding skills will allow you to avoid the areas of concern.
Trails around the mountain right now are very icy, hard, and slick. Historically, this has contributed to a number of accidents, particularly sliding falls with crampons on. I would not recommend glissading in these conditions. Certainly, glissading with crampons is never a good idea under any conditions. Crampons are great tools for helping you get around the mountains in these conditions, but they can be downright dangerous if you are sliding with any bit of speed. Quick self-arrest with your ice axe is the best way to stop a sliding fall. If you haven't practiced your self-arrest skills in a while, I'd recommend doing so in a safe location before venturing into angled terrain, including the Lion Head Winter Route. Crampons, an ice axe, and solid self arrest skills are needed for travel in steep terrain, which does include the Lion Head Winter Route and the summit cone.
It is looking like the meteorological stars are aligning for a good winter storm on Tuesday and Wednesday. The weather models are still debating about the track but all of them point to a significant weather maker. We will keep you posted on this in the upcoming advisories.
The Sherburne Ski Trail has a dusting of new snow on top of icy conditions.
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Avalanche Advisory Archives.
United States Avalanche Danger Descriptions.
Échelle Canadienne de risque d’avalanche.
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