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
Friday,
March 16, 2007 7:30 am
Good morning, this is Brett Kobernik with
the
Avalanche Watch:
An avalanche watch is
in effect for all the mountains of northern
Special Announcement:
UDOT is planning on
closing the highway in Little Cottonwood Canyon from entry 4 at Snowbird
through the town of
Current Conditions:
Temperatures dipped
below freezing at many locations last night which should produce a fairly
decent surface re-freeze of the snow.
Keep in mind that there are lots of stations that recorded temperatures
above freezing as well. Some are Snowbasin
Wildcat at 7800’, low of 37; Tom’s Hill
in Big Cottonwood at 9000 feet, low of 32 currently 35; Davis Peak south of Provo Canyon at 9700
feet, low of 32 currently 35. Winds are
generally less then 10 mph from the west gusting into the mid 20s at the more
exposed locations.
Snow and Avalanche Discussion:
Avalanche activity
reported from yesterday was, oddly enough, from within
ski resort boundaries in open areas in two separate incidents. One ski patroller in Big Cottonwood canyon
was taken by surprise when a northeast facing slope at around 9800 feet
released a slab that took him for a ride.
Luckily, he wasn’t buried and sustained minor injuries. It’s important to note that the surface was
still firm and hadn’t become damp or unsupportable at the time. There were also un-confirmed reports of
another slide at a ski area in Little Cottonwood where no one was caught. The point here is that if professionals who
deal with snow on a daily basis are getting caught off guard, backcountry
recreational users have equal or lesser odds.
While I was digging around yesterday it was easy to punch through the
superficial re-frozen surface and reach down into the damp faceted snow which
is not re-freezing. You’ll find similar
situations today in many areas. (I have
more photos of recent avalanches which I’ll post by around 9:00 am)
The main concern again
is warming temperatures weakening the snow surface to the point where it fails
or to the point where the faceted underlying snow fails as the slab above it
becomes weak and can no longer resist gravity.
The key to backcountry travel is to get off of steep slopes before they
become soft. If you can stick your boot
through the snow surface, you’re too late.
Also, keep in mind that even a supportable surface may not provide you
with 100 percent protection as was the case with the patroller in Big
Cottonwood. Its best give slopes some
extra lee way and get off them earlier then usual. Southeast facing slopes are the first to
soften therefore should be the first to move off of as the morning
progresses. South facing slopes are next
then southwest and west as the sun swings around in the afternoon.
Bottom Line for the
The danger of wet
sluff and slab avalanches is MODERATE this morning
and will rise to CONSIDERABLE again today on and below slopes of about 35
degrees and steeper, with daytime heating and sun. Slides can be triggered on slopes of all
aspects and elevations. CONSIDERABLE
means human triggered avalanches are likely and natural avalanches are
possible, so stay off of and out from under steep slopes this afternoon and
through the weekend.
Mountain Weather:
Today we’ll see mostly
clear skies with ridgetop temperatures around 40 and in the low 50s at 8,000
feet. Winds will be from the west in the
5 to 15 mph range. Warm temperatures
headline the weather news through the weekend with more of the same and little
if any refreeze the next couple of nights.
The next system is expected sometime Tuesday when temperatures will cool
off and bring the next chance for snow.
Announcements:
Yesterday, Wasatch Powderbird Guides flew in American
Fork, and the Sessions. Today they’ll be in American Fork, White Pine, Snake
Creek, the Sessions and Cascade. For
more info, call 742-2800.
The UAC and ACE are offering a day long Women’s Avalanche Awareness
class at Alta on March 22nd covering beacon use and basic safe
travel, terrain and snowpack information, for a nominal fee. For more details go to: www.altaarts.org.
Listen to the
advisory. Try our new streaming audio or
podcasts
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 a list of avalanche
classes, click HERE
For our classic text advisory click HERE.
To sign up for automated e-mails of our graphical advisory click HERE
We appreciate all the great
snowpack and avalanche observations we’ve been getting, so keep leaving us
messages 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.
Evelyn Lees will update this advisory by 7:30 on Saturday morning, and
thanks for calling.