In partnership with: The Friends of the Utah Avalanche Center, Utah Department of Public Safety Division of Comprehensive Emergency Management,
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Sunday, October 31, 2004 7:30 pm Happy halloween
evening, this is Drew Hardesty with the
storm is pounding the mountains with a vengeance. As of 5pm the upper Cottonwoods have picked
up 25-30” of 7% smoke. The
With this much snow and some hourly snowfall rates exceeding 2”/hr, avalanches are the rule and not the exception. The snow was exceedingly sensitive and both natural and human triggered avalanches ran on a variety of aspects above 9000’. Most ran on Friday’s rime crust or within the new snow, averaging 12-18” deep but reportedly not propagating very far. Typically, slope angles needed to approach 38-40 degrees to get things to run, and once they did, they would run fast and far, entraining a lot of snow along the way. At least two skiers were caught and carried in separate incidents in upper Little Cottonwood with only bruised egos to show for it. Slope cuts, cornice drops, and jumping on test slopes will tell you all you need to know for this type of hazard. That’s the good news. The bad news is that there was one report of an avalanche that pulled down into old snow. A cornice drop on a steep northeast facing slope in upper Little Cottonwood pulled out one of the ‘rogue’ wind slabs from last Thursday, producing a slide nearly 2’ deep and 50’ wide. Clearly, another inch of water weight combined with the thump of a cornice drop was enough stress to initiate failure in a layer that hadn’t produced any slides for a few days.
Remember, for the most part, the unopened ski areas are not doing control work, and are just as dangerous as the backcountry. Alta will be closed to backcountry touring on Monday to do control work.
The avalanche danger for Monday will be MODERATE on slopes steeper than 35 degrees. Human triggered avalanches will again be possible. The danger will be more pronounced in the upper Cottonwoods because they received the most snowfall. Tonight’s 10-20mph winds should be enough to deposit fresh wind drifts along the lee of ridgelines and steep breakovers that will be sensitive to the weight of a backcountry traveler. If the winds exceed the forecasted speeds, the danger will rise rapidly. Lastly, once the sun pokes through tomorrow, the danger of wet loose snow avalanches will also rise to MODERATE.
Lake effect snowfall should continue in earnest in the Cottonwoods through Monday morning. Another 4-8” are possible. The northwest winds are expected to become more northerly around midnight with ridgetop wind speeds expected to be 10-20mph. 8000’ highs will be in the upper twenties, with 10,000’ highs in the low teens. We’ll get a break for a few days before the next storm, slated to arrive on Wednesday.
If you are getting out, drop us a line or an email with any reports or observations from the backcountry. You can leave us a message at 524-5304 or 1 800-662-4140. Email us at [email protected], or a fax to 524-6301.
The information in this advisory is from the US Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.