Wasatch Cache National Forest
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Avalanche advisory

Sunday, February 20, 2005
Good morning, this is Drew Hardesty with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Sunday February 20th 2005, and its 7:30 in the morning.

Current Conditions:
With the remains of the storm moving through, skies are cloudy and snowfall has picked up again. With a couple inches of new snow overnight, storm totals across the range are 7”/1.23”H20 in the Ogden Mountains, 8”/.7” H20 in the Park City Mountains, 10”/.88” H20 in the Cottonwoods, and 5”/1” H20 in the Provo Mountains. Saturday morning’s south and southwesterly winds averaged 25-35mph with gusts to the 50’s in higher terrain, but lower elevation anemometers and observers reported drifting off the ridgelines as well. Winds in the Central Wasatch are now southwesterly averaging 15-20mph with gusts to 25, and about 10mph stronger in the Ogden and Provo Mountains.

Avalanche Conditions:
The new snow and strong winds conspired to create a localized natural cycle and widespread human triggered cycle in the Ogden, Salt Lake, and Provo backcountry yesterday. Apparently only one possibly pulled out into old snow (South Monitor) and amazingly, despite all the activity and close calls, only one person took a ride in the East Bowl of Silver Fork, but escaped unharmed. The reported naturals were along the highest elevations in upper LCC, above Red Pine Lake and in South Monitor. These averaged 12-24” deep and 100’ wide, all north to east facing and heavily wind-drifted. Nearly every observer that called in reported finding very sensitive cornices and soft slabs averaging 8-16” deep with the deepest reported 1-2’ deep off Rocky Point and the widest a remotely triggered slide in upper Snake Creek reported up to 600’ wide. Many of these were triggered at a distance, with some pulling out other pockets along the way. These slides were all on steep wind loaded slopes in the mid and upper elevations and not necessarily confined to north to east facing slopes, as the wind channeling and cross-loading allowed for most aspects to catch the new snow. Our 5am line at 364-1591 contains more details on the reported slides and I’ll have our avalanche list updated before noon.

I’m a little surprised that more avalanches didn’t step down into old snow, and am reluctant to believe that our mid-pack persistent instabilities are now dormant. For today, while the new wind drifts are likely to be a little less sensitive and widespread, they may possibly be larger and more dangerous and may still be triggered from a distance. Adding insult to injury will be some sensitive new wind drifts from this morning just to keep things interesting. It’ll be important to drop cornices, jump on test slopes, safely slope cut suspect areas, and watch for any signs of cracking and collapsing. Good safe travel protocol will be required again today.

Bottom Line (Salt Lake, Park City, Provo, and Ogden mountains):
The avalanche danger remains CONSIDERABLE on any steep wind loaded slope at the mid and high elevations. Any avalanche triggered on northwesterly through easterly aspects will have the potential to step down 1-4’ deep into weak faceted snow.

Mountain Weather: (Afternoon Weather Update can be found here.)
The remains of the Low will move through and we should see a burst of precipitation and stronger southwesterly winds this morning as the ripple moves through. Winds will pick up to the tune of 25-30mph, but should drop off to 15mph as the flow veers more westerly by afternoon. Snowfall will become more showery this afternoon and tonight, and we can expect 4-8” in favored areas over the next 18 hours. Temps will be in the twenties. A brief break Monday before the next system reloads for next week.

Yesterday, the Wasatch Powderbirds weren’t able to fly and are unlikely to get out today.

Thanks again to everyone who is sending in observations! This advisory is for you and it’s great to hear from people who use it. Please keep calling us at 524-5304 or 1-800-662-4140, or e-mailing us at [email protected]. Fax is 524-6301.

UDOT COTTONWOOD CANYONS HOTLINE FOR ROAD CLOSURE INFORMATION: 975-4838. Early birds can catch our early morning report at 6am by calling 364-1591.

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.

Bruce Tremper will update this advisory by 7:30 on Monday morning.

Thanks for calling.

For an explanation of avalanche danger ratings:

http://www.avalanche.org/~uac/ed-scale.htm