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

Saturday, March 17, 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 Saturday, March 17, 2007 and it’s 7:30 in the morning.

Avalanche Warning:

A special avalanche advisory has been issued for the mountains of northern Utah for the weekend. A weak snowpack and record breaking temperatures have created a CONSIDERABLE to HIGH avalanche danger, with both human triggered and natural avalanches probable. These dangerous avalanches have the potential to be very large and long running. Steep slopes and the areas below steep slopes should be avoided. People without excellent avalanche and route finding skills should stay out of the backcountry this weekend.

Special Announcement:

UDOT is planning on closing the highway in Little Cottonwood Canyon from entry 4 at Snowbird through the town of Alta at around 4:45pm today to do avalanche control work with explosives. This includes the main road as well as the bypass road. Interlodge restrictions will be in place by around 5pm. People should clear the south facing ridges and slopes from Mt Superior up to Grizzly Gulch by around noon in the event that control work needs to be implemented earlier. This work may also be performed Sunday afternoon as well.

Current Conditions:

It was down right tropical last night, and as of 6 am, temperatures are in the mid thirties to mid 40’s from the ridgetops down into the valleys. The westerly winds are generally in the 5 to 10 mph range, gusting into the mid 20s at the more exposed locations. Any surface refreeze is very localized and shallow, just a thin frozen crust over damp snow.

Snow and Avalanche Discussion:

No new avalanche activity was reported from the backcountry Friday. With afternoon explosive control work, a Big Cottonwood resort released two wet slabs, 2 to 5’ deep, starting out 60’ wide, and getting wider as they ran and a small slide was released above the Little Cottonwood highway.

This weekend, we may just be able to write the book on wet avalanches. There is the potential for just about every kind of wet snow slide - sluffs, wet slabs, glide crack releases, and even “corn slabs”, where the thin, frozen crust on the surface can be triggered. Any slide triggered will most likely step down, widen, or entrain more snow, resulting in a much larger and more dangerous slide. If you do get caught and buried, the dense debris of the wet slide will squash the air out of you and you may never take another breath. Wet snow slides are about as unpredictable and uncooperative as it gets, and avalanches are possible this weekend around the clock, 24 hours per day.

There is the potential for a few more very large and long running spontaneous slides to occur, similar to the Gobblers, Mineral, Bells Canyon and Thurston Peak slides from this past week. These isolated, long running slides could travel all the way down gullies to dry ground, such as in the Lisa Falls area and other drainage bottoms. If you head into the hills or mountains today, look above you or check out a map, avoid drainages and gullies below large, snow covered slopes.

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

The avalanche danger is CONSIDERABLE today on and below slopes of about 35 degrees and steeper, and may rise to HIGH this afternoon as the day heats up. Slides can be triggered on steep slopes of all aspects and elevations, and both human triggered and natural avalanches are possible. A few of these slides have the potential to be very large, dangerous, and long running.

Mountain Weather:

It’s out of the frying pan and into the fire today, with clear sunny skies and record breaking temperatures rising to near 60 at 8,000’ and into the mid 40’s at 10,000’. The westerly winds will be light, generally in the 5 to 15 mph range, with gusts in the 20’s across the highest peaks. Tonight, there will be a few high thin clouds, with temperatures remaining in the mid 30’s to low 40’s at all elevations. Temperatures will remain warm until Tuesday afternoon, when a Pacific cold front reaches northern Utah, bringing snow to the mountains and finally dropping temperatures below freezing for a few days.

Announcements:

Yesterday, Wasatch Powderbird Guides flew in American Fork, Snake Creek and the Sessions. Today if they fly, 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 22^nd covering beacon use and basic safe travel, terrain and snowpack information, for $30. 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.

Drew Hardesty will update this advisory by 7:30 on Sunday morning, and thanks for calling.