Wasatch Cache National Forest

In partnership with: The Friends of the Utah Avalanche 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, April 18, 2003

Good Afternoon. This is Ethan Greene with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory for the Wasatch Range near Salt Lake City. Today is Friday, April 18, 2003, and it’s about 6:00 in the evening.

Current Conditions:

A deep Pacific trough brought a nice blanket of new snow to the Wasatch today. Overnight the mountains picked up 4 to 8 inches of new snow at about 8,000’ and an additional 2 to 6 during the day. A small but intense cloud band put down over 17 inches in the Farmington Canyon area, and the Ogden mountains picked up about 10 inches of new snow. The Provo mountains received about 6 inches at 7,500’.

Today the winds were generally from the west in the 10 mph range. Some of the most exposed weather stations recorded gusts in the 20’s this morning. Temperatures climbed into the mid 30’s at 8,000’ and upper 20’s at 10,000’. Thin clouds in the mid morning allowed last night’s snow to become damp below about 9,500’, but in general the snow surface is quite soft.

Avalanche Conditions:

Snow conditions were quite variable before the storm, and that pattern hasn’t changed much since. In areas below about 8,500’ the old snowpack is still wet and mushy. These areas are now covered with a blanket of new snow and it will take a while for the old snow to refreeze. This wet snowpack is quite weak, so small avalanches could dig down into the old snow. Fortunately there isn’t much new snow in these areas, and the old snow is generally supporting its new load.

Above about 9,500’ were the old surface was frozen it is relatively easy to trigger small sluffs and soft slabs on steep slopes. These slides are either running on the old snow surface or a weakness within the new snow. They are generally less than 10 inches deep and are most dangerous if they can push you off a cliff or into a tree or gulley.

It looks like the snow is almost over, and if we don’t get much more our avalanche problems will stay near the snow surface. Fresh wind drifts will be easy to trigger on steep slopes, and if the sun breaks through the clouds the new snow will become quite active.

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

On Saturday the avalanche danger will still be LOW in areas that received less than about 6 inches of snow. In areas with more than about 8 inches of snow the avalanche danger will be MODERATE on slopes steeper than 35 degrees. As the sun breaks through the clouds in the afternoon the avalanche danger will rise on all sun exposed slopes.

Western Uinta Mountains: Click Here

Logan – call 435-797-4146 or Click Here.

Mountain Weather:

Snowfall rates should decrease this evening as the trough axis passes over the Wasatch. High pressure will begin to build in on Saturday as the trough moves off to the east. Expect snow showers tonight with about an inch accumulating by morning. Temperatures will drop into the low 20’s. The winds will shift to the northeast and remain in the 10 mph range. Tomorrow isolated snow showers are possible most of the day, but periods of sun are likely in the afternoon. The winds will continue to be light and temperatures at 8,000’ will rise to near 40 degrees. Mild weather is expected through the weekend with another storm forecast early in the week.

General Information:

To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, call (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 about 8:00 am on Saturday morning.

Thanks for calling!

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National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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