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
Sunday,
February 25, 2007 7:30 am
Good morning, this is Drew Hardesty with
the
I’ll be
giving a talk at the Wild Rose in the avenues Tuesday night at 7pm. It’s a higher level talk on Forecasting the Different Avalanche Dragons. Bring your Crazy Creek Chair and a picnic
basket.
Current Conditions:
Better
late than never. Friday’s storm provided much needed relief
and we have a few more good storms on the way.
It’s already snowing through most of the northern mountains with 6-10”
expected during the day. Warmer air
pushing into the area has mountain temperatures into the teens and low
twenties. The winds have shifted west
and southwest and have increased to 25-30mph along the exposed ridgelines. The sunny aspects crusted with the sun, but
the northerly aspects reminded me of the good old days.
Snow and Avalanche Discussion:
Explosive work in
uncompacted terrain in upper Little Cottonwood and mitigation to protect the
highways produced a couple good slides into old faceted snow up to 4’ deep on
steep north and northeast facing terrain.
Backcountry teams also found some excitement, particularly on steep
sheltered terrain in drainages above Mill Creek. The intrepid Bob Athey dropped a cornice in
upper West Porter, triggering a slide
24-30” deep and 80’ wide on a steep northeast facing slope at 9300’. Another up and coming observer remotely
triggered a large avalanche
(another photo)
into old faceted snow adjacent to Little Water Peak on a 33 degree northeast
facing slope at 9400’. Collapsing of
new wind drifts and the facet/crust combo should still alert the backcountry
wanderer to a still cranky pack.
Clear and cold from
yesterday hastened both the development of surface hoar and faceting of the
snow surface, which won’t bode well for today’s anticipated snow and
winds. Kobernik has a good photo here.
If the winds and snow amounts verify, I’d expect very tender new wind
drifts along the ridgelines and over steep breakovers. Remote and
sympathetically triggered slides will be likely in the new snow, which should
throw a wrench into classic route finding and runout zones. Drop a few
cornices and move through lower angled slopes and test slopes to verify the
initial hypothesis here.
Elsewhere in
depth-hoar land, the good news is that they’re becoming more difficult to
trigger. The bad news is that they are
becoming more difficult to trigger. Like
Tremper’s ‘monster out of the closet’ from a couple
weeks ago, you may go slope after slope without any activity, only to find a
superweak zone to trigger a hard slab into old snow 2-4’ deep. Their habitat remains on northwest through
east facing slopes above about 8500’.
Bottom Line for the
The danger is CONSIDERABLE
today on steep wind drifted slopes and in areas that receive the most
snow. All aspects at the higher
elevations are likely to be sensitive today due to poor bonding with
yesterday’s snow surface. The danger of triggering a slide
into old snow is MODERATE but likely unsurvivable. It takes considerable route finding skills
and self discipline to be wandering the backcountry these days.
Mountain Weather:
A strong moist
westerly flow will spread, at times, heavy snowfall in the mountains today with
6-10” in favored areas. The westerly
winds should pick up into the 30mph range along the higher peaks with temps in
the upper teens at 10,000’ and the upper 20’s at 8000’. We should get a quick break before a series
of storms move in Tuesday through Friday.
Announcements:
Yesterday, the Wasatch Powderbird Guides flew in
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.
I will update this advisory by 7:30 on Monday morning, and thanks for
calling.