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

Sunday, March 16, 2003

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Good Morning. This is Ethan Greene with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Sunday, March 16, 2003, and it’s 7:30 in the morning.

Current Conditions:

After a week of spring-like conditions, this morning winter is back! Overnight the mountains picked up 4 to 8 inches of new snow. Storm totals so far are 8 to 11 inches of snow and 1.5 inches of water in the Salt Lake Area Mountains and along the Park City Ridgeline. The Ogden and Provo Area Mountains picked up about 5 inches of snow and half an inch of water. By about 3 o’clock this morning the rain/snow line dropped to near 6,500’. The winds were in the 25 mph range from the south until about 1 am. Since then they have slowly been veering to the west and northwest and blowing in the 10 to 15 mph range. This morning temperatures are in the mid to low 20’s at both 8,000’ and 10,000’.

Yesterday’s snow and wind formed some punchy wind slabs on top of hard crusts in the upper elevation areas. In the afternoon the snow surface was damp up to about 9,000’ and wet below about 8,000’.

Avalanche Conditions:

Yesterday it was rather blustery in the mountains. Gusty southerly winds blew the new snow around and formed wind drifts along both the upper ridgelines and mid elevation terrain features. These recent wind drifts were generally 6 to 18 inches deep and a couple of winter travelers were able to trigger small pockets in steep terrain. Although these new wind drifts were rather benign yesterday, they are sitting on low density new snow or firm ice crusts that formed last week. Strong hard snow sitting on weak soft snow is a perfect recipe for an avalanche. Today you should watch your step around any fresh wind drift and remember that as more snow falls and the wind continues to blow the danger will increase.

Deep slab avalanches are still possible in the same areas that have been haunting us all year. The most likely way to trigger one of these deeper slides would be with a big trigger such as several people or snow machines on one slope at the same time. Triggering a smaller avalanche or dropping a large cornice could also produce a deep slab avalanche. Remember this year the deep slab avalanches have generally been on steep north through east facing slopes that have a relatively thin snowpack.

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

The avalanche danger today is MODERATE on all slopes with fresh wind drifts. Along the most exposed ridgelines and in areas that receive more snow and wind the danger may rise to CONSIDERABLE. Conditions will be changing during the day so make sure your stability evaluation changes accordingly. There also remains a MODERATE danger of triggering a deep slab avalanche especially in very steep terrain that has had a thin snowpack most of the year.

Western Uintas – call 1-800-648-7433 or click here for weekend and holiday forecasts.

Mountain Weather:

A large Pacific trough is moving inland and over the western U.S. The strong short wave that bought us snow overnight is moving out to the northeast this morning. Today expect cloudy skies and snow showers throughout the day. An additional 4 to 8 inches (Ogden: 3 to 6; Provo: 2 to 5) could accumulate during the day. Temperatures will rise into the mid 30’s at 8,000’ and low 20’s at 10,000’. Winds will be from the northwest in the 10 to 20 mph range this morning and 5 to 15 mph range this afternoon. Over the next few days this broad trough is forecast to form a large cut off low over the central U.S. Locally we can expect snow showers, cooler temperatures, and northerly winds for the next few days.

General Information:

Wasatch Powderbird Guides will probably not be flying today. For more information call (801) 742-2800.

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.

Bruce Tremper will update this advisory by 7:30 on Monday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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