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”
AVALANCHE ADVISORY
Wednesday,
December 19, 2007 7:30 am
Good morning, this is
Current Conditions:
It’s the
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
Avalanche Discussion:
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.
Mountain Weather:
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.
Announcements:
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.