Wasatch Cache National Forest
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 Salt Lake County.

“keeping you on top”

AVALANCHE ADVISORY

Friday, February 16, 2007 7:30 am
Good morning, this is Evelyn Lees with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Friday, February 16, 2007 and it’s 7:30 in the morning.

The Banff Mountain Film Festival will be held at Kingsbury Hall next Tuesday and Wednesday, February 20 & 21^st. Tickets are $7.50 per show and available at Kingsbury Hall, Art-Tix, the Salt Lake and Sandy REI stores, and the Outdoor Recreation Program at the U of U. Shows start at 7pm each night. (CLICK FOR DETAILS)

Current Conditions:

Snow is falling at most mountain stations this morning, with overnight snow totals in the 3 to 6” range. 24 hour snow totals are 2 to 10”, with water equivalents of ¼ of an inch to almost 1 ½ inches of water. The heaviest snowfall has been in parts of the Ogden area mountains and in Little Cottonwood. The northwesterly winds increased dramatically overnight, averaging 15 to 25 mph at most stations, with gusts into the 30’s and 40’s. Across the highest peaks, speeds have been 40 to 50 mph, with gusts to 70. Temperatures graphs show an impressive upward march, with stations 10 to 15 degrees warmer than yesterday morning. The snow is inverted, dense on light, with a thin rime crust mid storm in many locations.

Recent Avalanche Activity:

Yesterday, there were many more reports of widespread collapsing throughout the range. Sensitive, small wind drifts were triggered up to 8' long by 2' deep. One soft slab was released on facets (Photo), 18" deep by 40' wide, on a north facing slope at 9,700’ with a ski cut. Snow pits continue to show easy failure on the buried facets and around a sun crust that formed Tuesday on southeasterly facing slopes.

Snow and Avalanche Discussion:
The first avalanche problem today is the fresh, dense wind drifts formed by the strong, northwesterly winds that have been blowing overnight. These drifts will be most common along the ridgelines on east and southeasterly facing slopes, but due to the strong wind speeds, snow will also be drifted well off ridgelines. Watch for cross loading around terrain features such as rocks and rollovers at mid and low elevations. The dense, warm drifts may be stubborn, but could then break out wide once they get moving. Any new wind drifts triggered could easily step down into old snow.

The second avalanche problem is the new snow is once again overloading the deeper, weak faceted layers. Slides failing on these facets will take out two storms worth of snow, and avalanche depths could be 1 to 3’ deep and pull out wider than expected onto low angle adjacent slopes. Slopes that slid last cycle could repeat. Slides can be triggered from a distance and natural avalanches are possible today, so avoid travel below and adjacent to steep slopes.

Bottom Line for the Salt Lake, Park City, Provo and Ogden area mountains:

The avalanche danger is CONSIDERABLE on any slope steeper than about 35 degrees, especially with recent drifts of wind blown snow. CONSIDERABLE means human triggered slides are probable and natural avalanches possible. Pockets of HIGH danger exist in areas that received the most snow and wind, including the upper elevations of Little Cottonwood and the Ogden area mountains. People without good snow stability and avalanche skills should avoid backcountry travel today. Those heading into the backcountry should choose routes and tours with lots of options to stay on low angle terrain. Natural avalanches and remotely triggered avalanches are possible, so avoid travel below steep slopes.

Mountain Weather:

A strong, moist northwest flow will remain over the area through this afternoon. Light snow will continue this morning, before tapering later today. The strong northwesterly winds will persist all day, with ridgeline averages in the 25 to 35 mph range, and gusts to near 50. Speeds will be greater along the most exposed ridges. Temperatures will remain near freezing at 8,000’ and near 20 at 10,000’. Winds will decrease tonight as high pressure builds in for the weekend.

Announcements:

Yesterday, the Wasatch Powderbird Guides did not fly, and today they most likely be shut down for wind and snow, but if possible, they will be in American Fork, Cardiff, Days, Silver and Grizzly. With questions regarding their areas of operation call 742-2800.

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.

Brett Kobernik will update this advisory by 7:30 on Saturday morning, and thanks for calling.