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

Monday, December 17, 2007 7:30 am
Good morning, this is Drew Hardesty with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Monday, December 17, 2007 and it’s about 7:30 am.

Upper LCC between Snowbird Entry 2 and Superior will be closed intermittently between 7:30 and 8:15 this morning as UDOT sights-in their avalauncher.

Current Conditions:

Skies are mostly cloudy this morning with temperatures in the low twenties and high teens. The south to southwesterly winds, however, are playing the spoiler in the mountains as the afternoon’s 25-35mph winds only warmed up the jets for last night’s averages of 30-40mph, with gusts to near 60. This will wreak havoc with the riding conditions, but – we’ve got a couple good looking storms on tap to soften the blow.

Avalanche Discussion:

In response to the wind, which was more central to the discussion up north, the Ogden area mountains shed a few shallow naturals in the upper cirques. Others in the central Wasatch initiated a couple wind pockets, but these were small and relatively harmless. Whatever snow that didn’t blow to Evanston will now have been deposited as a myriad of hard and soft slabs in unusual areas, bumping the danger a notch. True, there’s not much snow to be blown off the southerly aspects, but with some anemometers off the ridgelines blowing 20-30mph, you’ll find scalloped and pillowy snow pockets in any deceleration zone and beyond. Remember, the hard drifts have a tendency to allow you get way out on them before releasing. Might be with the 3^rd skier or rider as well. Many of the new drifts will be sitting on what amounts to a house of cards of the rapidly weakening surface snow from the past week. Probably be good to show a hint of restraint and take the blinders off to the smooth, and at-times-supportable, wind pockets. Some naturalling may have already occurred.

What would our forecast be without mentioning the weak snowpack structure on the shady slopes above 9000’? All the best climbers I know suffer from short term memory issues, but this doesn’t play well for the backcountry avalanche situation. It was only three days ago that folks triggered slides into old snow up to three feet deep. Collapsing of this weak layer persists. The structure remains inviolate. The energy and propagation potential, readily found with most stability tests, are still red flags.

Bottom Line:

The avalanche danger now has pockets of CONSIDERABLE danger from the moderate to strong winds. The pattern will not be consistent, but caution or avoidance should be exercised in areas with obvious wind effect. The danger for triggering an avalanche into old snow up to 3’ deep remains MODERATE on steep northerly facing slopes above about 9,000’.

Mountain Weather:

A clipper to the north will only produce some cloudiness for the Wasatch, but it sets the stage for a couple good storms for the week. The southwesterly winds will continue to blow 30+ then back down to a more reasonable 20mph by the afternoon. Temperatures will be in the upper teens and low twenties. The first system, slated for Tuesday night, comes in fairly warm on a westerly to southwesterly flow, and looks to provide a relatively even blanket of a foot or more of snow. Although I am skeptical of a few components of the later-in-the-week system, it should still be a decent shot of snow.

Announcements:

The Wasatch Powderbird Guides will be not be flying today.

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.

Brett Kobernik will update this advisory by 7:30 Tuesday morning.