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, December 15, 2002

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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, December 15, 2002, and it’s 7:30 in the morning.

Current Conditions:

Overnight the winds have been howling across the Wasatch Range. Along the highest peaks southerly winds have been in 30 to 40 mph range with the occasional gust over 70 mph. Mid-elevation winds have been in the 25 mph range with gusts over 50 mph. Temperatures dropped into the mid to upper 20’s at most locations. No new precipitation has been reported as of 6:00 am, but with a cold front knocking at our door, 4 to 6 inches of snow are expected during the day.

Avalanche Conditions:

The backcountry snowpack contains a myriad of weak layers, and with snow and wind in the forecast the question is not if we will see avalanches but when will they start. Overnight the winds were quite strong and may have already built a few sensitive wind slabs. As a cold front moves through the Wasatch Range today, more snow and wind will increase the load on our very fragile snowpack. The weakest snow is near the surface on northerly or shady slopes, but many southerly aspects are covered by a firm surface crust that will be a good sliding layer if the new snow comes in fast.

As you are traveling around the backcountry today pay attention to the consistency of the new snow. As the new snow layer builds and forms a cohesive slab the avalanche danger will rise. If more snow falls than expected, or if the winds remains strong most of the day the avalanche danger will increase very fast.

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

The avalanche danger is MODERATE this morning but may rise to CONSIDERABLE this afternoon as new snow accumulates. A considerable avalanche danger means that natural avalanches are possible and human triggered avalanches are probable. Winter travelers may want to avoid traveling on or underneath steep slopes during the afternoon.

Mountain Weather:

A fast moving short-wave trough will bring wind and snow to the Wasatch Mountains today. Strong southerly winds this morning will shift to the west as the front passes and decrease in speed. Ridge-top wind speeds could remain in the 20 to 30 mph range most of the day. The cold front is forecast to move into the Wasatch Range during the mid morning and thunder and lightning are possible. Areas favored by westerly flow will receive the largest snow accumulations, but four to six inches are expected. The Logan Area Mountains may receive larger snow amounts. Temperatures will be cooling most of the day. High temperatures will be in the mid 30’s at 8,000’ and mid 20’s at 10,000’. By this afternoon temperatures at 10,000’ will drop into the upper teens. Monday skies will be mostly cloudy with a change of snow. Another storm is forecast to affect the Wasatch on Tuesday.

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 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