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”
February 29, 2008 7:30 am
Good morning, this is
Skies remain clear
under the soon-to-be-out-the-door ridge of high pressure. Temperatures are in the mid-20’s up high,
with the cold air sinks registering overnight lows in the mid to upper
teens. This morning, winds aloft are
light from the northwest, although they bumped into the 20-25mph range with
gusts to 35 during the overnight hours. Riding
conditions remain excellent in the mid and upper elevation shady slopes, with
what amounts to semi-corn conditions on the steeper sunny aspects. On another
note, there have been at least 3 negative interactions with moose on some of
the popular trails in
Snow and Avalanche Discussion:
The only news we heard
about, beyond a few wet sluffs, was a natural cornice fall along the
As winter shifts to spring, so our focus shifts to include the southern end of the compass. Faceted snow there above a melt freeze crust sits buried 1-2’ beneath the snow, and was responsible for a number of wet slab naturals and close calls with human triggered slides on Tuesday and Wednesday. Rapid warming also contributed to the number of incidents on the steep sunny exits back on Saturday, with the loose wet snow instigating a number of ‘unintentional hip checks’ to the way-late skiers. It’s time to calibrate our timed exits and windows on the steepest sun-exposed slopes. By the time you’re sinking in and/or seeing roller balls, say by about late morning, you’re too late.
Other weak layers on and just beneath the snow surface abound and it will again be important to map these prior to Saturday’s quick hitting cold front. Surface hoar and graupel are two of the potential players, and are both driven by localized weather events. The graupel, driven by localized updrafts and convective instabilities can easily be found in one drainage and not another. Surface hoar, often sensitive to cloud cover, wind, and temperatures, too, can be developed or destroyed in neighboring sub-drainages. And until they come up with a weak snow detector, we’re stuck with mapping snow surfaces and poking in the snow once they’re buried. As our good friend Lynne Wolfe (she’s the editor of the Avalanche Review) from the Tetons likes to say, today’s snow surface is tomorrow’s weak layer.
Bottom Line for the
Isolated pockets of MODERATE exist in the shady mid and upper elevation terrain for triggering newer wind drifts and graupel slabs. On the other end of the compass the danger will rapidly rise to MODERATE on all the sun exposed slopes with daytime heating. Sagging cornices will again be concern – give them a wide berth there on the windward side of the ridgelines.
We’ll have clear skies, and with the ridge shifting slowly to the east, the winds will back to the southwest but remain at or less than 15mph. 8000 and 10,000’ temps will again be in the low forties and thirties, respectively. A vigorous, but fleeting cold front moves through tomorrow afternoon that should be good for 6-10” in northwest-flow favored terrain, with a few minor disturbances on tap for early next week.
The Wasatch Powderbird Guides flew yesterday in Mineral,
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If you see any avalanches or interesting snow conditions, please leave us 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.