In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and
“keeping you on top”
December 19, 2007 7:30 am
Good morning, this is
good four letter “s” word this morning – snow!
The first in a series of storms has laid down 6 to 12” of about 7%
density snow, with the greatest accumulations in Big Cottonwood, the northern
No new avalanche activity was reported from the backcountry yesterday, though it was still possible to crack out some of the old hard wind slabs, especially where they are sitting on surface hoar or light density snow mixed with near surface facets.
The new snow is falling on a wide variety of old snow surfaces, which will be hidden beneath a coating of white today. This will make backcountry travel tricky, as the bonding of new snow is dependent on the old snow surface that you can’t see and which varies over very short distances. A small test slope in one location may not be representative of a larger, adjacent slope. The steep, wind drifted slopes will be the most sensitive, and should be avoided. Approach other steep slopes with caution. The avalanche danger will peak this morning during the period of heaviest precipitation, or any time you’re in an area where the wind speeds increase and start to drift the snow.
And then there is the continuing
avalanche concern of the old
October facets near the ground, which are refusing to gain strength in many
locations. This deep weak layer is found
on northwest, north, and northeasterly facing slopes, above about 9,000’, and is
most widespread in
Bottom Line for the
The avalanche danger is CONSIDERABLE on any steep, wind drifted slope, where natural avalanches will be possible, and human triggered slides probable. Particularly avoid the northwest, north and northeasterly facing slopes, above about 9,000’ where slides have a potential to break out on deeper weak layers. The avalanche danger is MODERATE on steep slopes without wind drifting and without the layer of facets near the ground. Slopes less steep than about 35 degrees have a generally LOW avalanche danger today, and will have very good turning and riding conditions. There will be an increasing avalanche danger Thursday with additional snow and strong winds in the forecast.
A moist storm system moving across the area this morning will bring another few hours of light to moderate snow, before tapering off around noon. An additional 3 to 6” of snow is possible. The southwesterly winds may increase into the 10 to 20 mph range, with gusts to 30, with the highest ridges and peaks having hourly averages of up to 20 to 30 mph, with gusts in the 40’s. Temperatures will be in the low 30’s at 8,000’ and in the upper teens at 10,000’. After a short break this afternoon and evening, it will be “full conditions” tomorrow as a second, stronger storm arrives with more snow and powerful, southwesterly winds.
The Wasatch Powderbird Guides will be not be flying today.
For an avalanche education class list, click HERE.
If you want to get this avalanche advisory e-mailed to you daily click HERE.
The UAC has temporary job openings for doing avalanche outreach in more rural areas. Click HERE for info.
UDOT highway avalanche control work info can be found HERE or by calling (801) 975-4838.
Our statewide tollfree line is 1-888-999-4019 (early morning, option 8).
For our classic text advisory click HERE.
If you’re getting out and see anything we should know about please let us know. You can leave a message at (801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 801-524-6301)
The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
Bruce Tremper will update this advisory by 7:30 Thursday morning.