Wasatch Cache National Forest

In partnership with: The Friends of the Utah Avalanche Forecast Center, Utah Department of Public Safety Division of Comprehensive Emergency Management, Salt Lake County, and Utah State Parks

The Utah Avalanche Center Home page is: http://www.avalanche.org/~uac/

Avalanche advisory

Friday, February 28, 2003

If you want this advisory automatically e-mailed to you each day for free, click HERE.

If you want recent archives of this advisory, click HERE.

To e-mail us an observation, CLICK HERE.

To see photos of recent avalanche activity CLICK HERE (Will be updated 2-28-03)

To see a list of recent avalanches, CLICK HERE, (Updated 2-28-03)

NEW! Click here to view the advisory with a cool, new glossary of avalanche terms!

Good Morning. This is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Friday, February 28, 2003, and it’s 7:30 in the morning. We would like to acknowledge one of our partners, the Friends of the Utah Avalanche Center, generously supported by Alta Ski Lifts.

Current Conditions:

A little bit of sun yesterday put a sun crust on all slopes except the straight north facing ones, where you can still find about 8 inches of very nice powder snow. Winds are calm this morning with ridge top temperatures in the single digits.

Avalanche Conditions:

Yesterday, backcountry explosive testing produced three large avalanches in the Salt Lake area mountains. Two were in Cardiff Fork and one in Day’s Fork, both of which are backcountry terrain just north of Alta. I have the details of these slides in the usual locations, on our 364-1591 detailed recorded advisory, and on the list of avalanches at www.avalanche.org, click on Salt Lake, then on Advisories, then on list of avalanches. All of these avalanches “broke into old snow”, as we say, which means that it fractured into deeper weak layers of weak, faceted snow. Two of them broke into the deep, depth hoar layers near the ground and the other broke into a shallower layer of weak, faceted snow. One in upper Cardiac Bowl took out 40 old tracks from backcountry skiers plus a climbing track. All were north through east facing, about 150 feet wide, 2-3 feet deep, on 38 degree slopes and they fit the usual pattern we have seen all season, namely, steep, areas with a thin snowpack.

If nothing else, Utahn’s are getting a good education this season. Here in Utah we’re used to having a stable snowpack, honest and safe neighbors, where it’s sunny every day, everyone is good looking and all the children are above average. But suddenly, we find that we have moved to a bad neighborhood in a big city where you just never know what’s going to happen when you walk to the corner grocery store. People are jumping into a lot of steep slopes without incident, but there’s just enough isolated booby traps around to keep you looking nervously over your shoulder. We keep hoping that a huge storm will come along and wash all our troubles away, but instead, the weather just keeps teasing us along, just adding enough weight to keep us near the edge—and it’s been like that for months now. In other words, this is just not the year to mess around with steep slopes.

Another less dangerous problem is that the new snow is not bonding very well to the old ice crust. Yesterday, the new snow was sluffing easily in loose snow avalanches, which usually are not much of a problem unless one takes you over a cliff or into a terrain trap such as a gully. Finally, one thing to keep in the back of your mind, these clear, calm, humid conditions has formed widespread areas of frost on the surface of the snow, which we call “surface hoar”. Once buried, it becomes a very thin and very weak layer that could produce avalanches in the future. Keep this in mind for our next storm.

Bottom Line (SLC, Park City, Ogden and Provo Area Mountains):

The avalanche danger is MODERATE on all slopes steeper than about 35 degrees, and above about 9,000 feet. Moderate means human triggered avalanches possible. Sluffs and soft slabs triggered within the new snow have the potential to pull out layers of old snow, creating larger more dangerous avalanches. Slopes less steep than about 35 degrees have a generally LOW danger. 35 degrees is about the steepness of a black diamond slope at a ski resort.

Note: the western Uinta Mountain are at least a notch higher on the danger scale than the Wasatch Range. Western Uintas – call 1-800-648-7433 or click here for weekend and holiday forecasts.

Mountain Weather:

For a change, we have a broad trough stuck over the western U.S., which will continue to bring us cloudy, unsettled weather with occasional snow showers. Today, we will have unstable air with partly cloudy weather this morning with thicker clouds boiling up in the afternoon again with a few light snow showers. Ridge top winds should be light from the north through west with ridge top temperatures in the single digits and down at 8,000’ the day time high should be in the mid 20’s. Saturday it looks like mostly cloudy with light snow showers. Sunday should be clear. All the computer models disagree after that but it looks like we’ll have more clouds and occasional snow showers through most of next week.

General Information:

Weather permitting, and depending on visibility, Wasatch Powderbird Guides will be flying in one or all of the following areas: Silver, Days, Cardiff, White Pine, Lambs Canyon and American Fork with a possible home run in Grizzly Gulch.

To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, please leave a message on our answer machine at (801) 524-5304 or 1-800-662-4140, or email to [email protected] or fax to 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.

I will update this advisory by 7:30 on Saturday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

http://www.avalanche.org/usdanger.htm