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

Thursday, December 28, 2006 7:30 am
Good morning, this is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Thursday, December 28, 2006 and it’s 7:30 in the morning.

Current Conditions:

My suspicions about this storm yesterday proved well-justified. It was yet another storm of huff-and-puff-but-not-much-fluff. A mighty 2-5 inches of pasty snow fell yesterday but hey, at least the winds were blowing hard enough to tip over a tractor. Yesterday’s ridge top winds blew from the southwest, 35 gusting into the upper 50’s for much of the day. The places that get hit hard from the southwest winds had a lot of damage, such as the Park City ridgelines. As the energy of the storm dove south in late afternoon, the ridgetop winds dropped to zero, so we couldn’t squeeze more than about an inch out of the northwest flow last night. This morning, the ridge top winds are light from the north with ridge top temperatures in the mid teens.

Snowpack and Avalanche Conditions:

Yesterday not a lot of people were out in the backcountry, but the hard working and cagy Bob Athey and Mark White were able to intentionally trigger a hard slab on a wind-loaded side in Days Fork at 9,500’. It broke 1-2 feet deep on faceted snow beneath a buried rime crust and stepped down into deeper faceted snow. They were able to trigger it from the flats near the slide. Photo 1 Photo 2, Photo 3 Also, all the ski resorts reported widespread areas of sensitive, soft slabs on all the wind drifted slopes, but for the most part, they were shallow and manageable. The exception was an explosive-triggered slide in Daily Chutes near Park City which broke up to 6 feet deep to the ground. I think wind loading was invented in the Daily Bowl area and that kind of place really gets hammered by these south and southwest winds. You should also be very cautious of the Park City ridgeline and Snake Creek where significant wind loading occurred yesterday. The wind slabs will range from soft to hard and they will look smooth and rounded. They often feel “slabby” and sound hollow. An inch of new snow overnight may conceal them a bit but definitely do a lot of probing and investigating as you travel today. If you find one on a steep slope, you should definitely avoid it.

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

The danger is MODERATE on any slope steeper than about 35 degrees with recent deposits of wind drifted snow less than a foot deep soft slabs. The danger is CONSIDERABLE on slopes with wind drifts more than a foot deep and hard slabs. You will find pockets of these wind slabs along many of the upper elevation, wind exposed slopes. The danger will be LOW in non-wind drifted slopes with less than 4 inches of new snow.

Mountain Weather:

Today the ridge top winds will shift from the north to the northeast and they may pick up and blow as strong as 30 mph with higher gusts, which will give us a whole new set of wind slabs. We will get a few more light snow showers this morning but probably won’t add up to more than an inch. We should have clouds hanging around the mountains for most of the day. Ridge top temperatures will be in the mid teens. Skies should clear by tonight and we will have warmer temperatures and clear skies for the weekend.

The extended forecast calls for clear weather through the weekend with a few high clouds on Tuesday and another chance for some snow about a week from today.

Announcements:

If they can get out, The Wasatch Powderbird Guides will fly today in Silver, Cardiff, Days and American Fork.

The Rescue Training Center at the Canyons Resort is up and running now at the top of the gondola.

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We appreciate any snowpack and avalanche observations you have, so 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.

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