| Posted: 6:37 a.m., Tuesday, December 6, 2005 |
Huntington Ravine has MODERATE avalanche danger today. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steeper terrain. We are currently not forecasting for the Escape Hatch due to lack of snow.
Yesterday we watched W winds continue to transport recent snow into both Ravines until early afternoon when the speeds slowed down and the Summit folks also stopped reporting blowing snow. The start zones with E and SE aspects developed the most new windslab though other areas gained their fair share as well. The different strata that form the upper layers of our current snowpack are a portrait of a classic "heads up" snowpack. At the surface we have a layer of soft windslab that may be difficult to discern as a slab if you're not keeping your avalanche eyes open. Remember that any snow that has cohesive properties can be considered a slab. Beneath this windslab we can observe a thin layer of uncohesive powder that fell before winds began to pick up a couple of days ago. This layer may be difficult to discern from the soft slab above with the naked eye. Tests such as a shovel shear or compression test may help to detect this thin layer but make sure you're in a safe location when you start digging in. Below these upper layers is a classic bed surface that comes in the form of bulletproof snow hardened by last week's rain and big drop in temps. This combination provides the slab, weak layer and bed surface needed for an avalanche. What else is needed for the slope to slide you wonder? A trigger, that's what. We have come down from yesterday's rating of Considerable when the potential for natural avalanches was more of an issue. Under the current rating we agree that natural avalanches are now unlikely but it's the two legged triggers we need to be concerned about. If you're out today on an adventure try to stick to areas where the winds scoured slopes down to the old surface. Also keep a close eye on the slopes above you just in case someone else is enjoying the same area as you. Light snow, occasional clouds and flat light may combine for tough visibility today. You may be on a relatively safe scoured section of slope but it's all for naught if someone's kartwheeling across a pocket of windslab in the starting zone above!
The hard old surface should also be acknowledged today for the trouble it may create for travelers. All trails are very slick and crampons and an ice axe are essential for travel on open terrain of any steepness. Self arrest will only be effective if executed immediately after a slip otherwise speed and the snow density may make attempts futile. We had a serious accident on Saturday when an experienced climber was blown off his feet while approaching the bottom of ODell's Gully. The victim took a 400'(125m) uncontrolled slide down the slope and into the talus below. The party began a self rescue before being assisted by rescuers. More than 30 people participated in this difficult rescue that lasted late into the evening.
Don't wait any longer to refresh your avalanche skills. Pull out your beacon, practice, and spend a couple bucks on a fresh set of high quality batteries. Review your safe travel rules, techniques for assessing snow stability, and sign up for an avalanche course. We now have all the avalanche courses offered in the Valley this winter on our website, tuckerman.org. Sign yourself or a loved one up now!
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Avalanche Advisory Archives.
United States Avalanche Danger Descriptions.
Échelle Canadienne de risque d’avalanche.
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