In partnership with: The Friends of the
Utah Avalanche Center, Utah Department of Public Safety Division of
Comprehensive Emergency Management,
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Avalanche INFORMATION
Sunday, October 31,
2004 7:30 pm Happy halloween
Good
evening, this is Drew Hardesty with the
Current Conditions:
This
storm is pounding the mountains with a vengeance. As of 5pm the upper Cottonwoods have picked
up 25-30” of 7% smoke. The
Avalanche Conditions
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.
Bottom Line:
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.
Mountain Weather:
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.
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