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, December 22, 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, December 22, 2007 and it’s about 7:30 am.

There will be a local highway block in Big Cottonwood canyon for a few minutes this morning around 8 am for control work in the Stairs Gulch slide path. Please avoid travel in that area this morning.

Current Conditions:

Clear skies have brought cold temperatures to the mountains, with most stations coming in at 0 to 10 below this morning. The northwesterly winds are generally less than 15 mph, except for a few of the highest peaks, which have speeds in the 20 to 30 mph range. New snow totals since mid week are about 3 1/2’ in the Cottonwoods and 2-3’ Ogden, Park City and Provo area mountains. As the new snow continues to settle, and trail breaking, turning and riding conditions are improving greatly.

Avalanche Discussion:

Yesterday, there were no human triggered avalanches reported from the backcountry, though all reports I received were from people wisely exercising caution. There were, however, big deep slides failing on facets near the ground from explosive control work at the resorts in the Salt Lake and Ogden area mountains. These were on northwest, north and northeasterly facing slopes, above 8,500’ in the Ogden mountains, 9,000’ on the Park City side of the range, and about 9,500’ in the Cottonwoods. The Logan area mountains are much more unstable, and had a widespread natural avalanche cycle, with remotes and large collapses continuing Friday.

While the new snow is continuing to strengthen and settle, 3 feet in 3 days means there still are some new snow concerns. First, avoid any slope with wind drifts, which were still cracking yesterday. Also, some slopes still signs of poor bonding to the old snow surface from Tuesday, consisting of small facets or thin sun crusts. And finally, as the day warms, the snow on the steep sunny slopes a may become more sensitive, and it will be easier to trigger snow slides on the steep slopes.

There also continue to be places where a person could still trigger a slide on the weak facets near the ground. These would be in shallower snowpack areas, including steep rollovers or in shallow rocky areas, on the steep, upper elevation shady slopes. A slide triggered in a shallow area will propagate into the deeper snow pack, resulting in large, dangerous slides 3 to 5 feet deep.

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

Today is the day – Sun, Snow and Saturday – it is the perfect Utah combination for an avalanche accident. It is possible for a person to trigger a deep, dangerous slide today, so avoid steep terrain today, use your best travel procedures of only one person on a slope at a time, and think about consequences. Don’t ruin the holidays with an accident - there will be many more powder days to come with a stronger snowpack.

The avalanche danger is CONSIDERABLE on slopes steeper than about 35 degrees, on upper elevation northwest, north, and northeasterly facing slopes where avalanches could break out 3 to 5 feet deep. Also, avoid any steep slope with drifts of wind blown snow, which will be most widespread in open mid and upper elevation terrain with an easterly component. Other slopes steeper than about 35 degrees have a MODERATE danger, and you will need to carefully evaluate them as you travel, and be willing to change your plan.

Mountain Weather:

Skies will be clear this morning, with temperatures warming into the low 20’s at 8,000’ and the single digits at 10,000’ today. Winds will be from the northwest, less than 15 mph at most mountain locations. However, the highest peaks and ridges may have speeds in the 20 to 30 mph range, with gusts in the 40’s until about noon. Clouds will start to increase this afternoon ahead of a fast moving system that will bring another 6” of snow tonight into Sunday morning, with slightly stronger northwesterly winds. Another medium size storm should impact the area on Monday and Monday night.

Announcements:
Wasatch Powderbirds will operate outside of the Tri Canyon area this Saturday, and they will use a Monday exchange in the future. So today they will be in American Fork and possibly the Cascade Ridge area.

For an avalanche education class list, click HERE.

If you want to get this avalanche advisory e-mailed to you daily click HERE.

The UAC has temporary job openings for doing avalanche outreach in more rural areas. Click HERE for info.

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 our classic text advisory click HERE.

If you’re getting out and see anything we should know about please let us know. You can leave 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.

Drew Hardesty will update this advisory by 7:30 Sunday morning.