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

Thursday, March 27, 2003

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Good Morning. This is Evelyn Lees with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Thursday, March 27, 2003, and it’s 7:30 in the morning.

Current Conditions:

Unfortunately, the meteorological ingredients did not quite come together to give us the big snow numbers we had hoped for. Storm totals as of 6 am are, 6 to 12” in the Ogden, Park City and Salt Lake mountains. Up north, the Logan mountains did quite well, with 12 to 22” storm totals. The Provo mountains are reporting only a few inches of snow at the lower elevations, but may have received snow amounts of up to a foot at the higher elevations. The dense snow averaged 13%, with water equivalents over 1” in the parts of the central Wasatch. The westerly winds were very strong overnight, in the 30 to 45 mph range, with the most exposed locations averaging 50 to 70 mph. This morning, the winds have decreased into the 10 to 20 mph range at all but the highest elevations. Temperatures are a wintry 10 degrees at 10,000’.

Avalanche Conditions:

The strong winds have sculpted the dense snow into widespread stiff, wind slabs. One report from the backcountry late yesterday afternoon indicated that these drifts were already breaking easily on steep slopes and running fast and far on the underlying crusts. The strong winds drifted the snow even in the more sheltered the mid and low elevation terrain. Expect sensitive drifts in both the usual and unusual places, including well off the ridgelines, in trees, around gully walls and at changes in slope angle. In more sheltered areas, the drifts may be only 8 to 10” deep, but at the higher elevations, slides could easily break out two feet deep. Some of these drifts will be easily triggered by backcountry users on steep wind loaded slopes, while other drifts will be stubborn, and may not break until you are several turns into the slope.

On the steep shady northwest through easterly facing slopes, there is a chance slides could break into one of several more deeply buried weak layers, creating wider, deeper slides. The most likely failure would be near the crust formed by Sunday’s rain and warm snow, though slides could step down to near the ground. It may be possible to trigger slides from a distance today. The most likely place to find this sort of trouble is on steep northerly through easterly facing slopes above 9,500 feet, especially in rocky areas with a relatively thin snow pack.

The skies will become partly to mostly sunny in many mountain locations today, and the avalanche danger will rise on and below steep sunny slopes if the snow heats up.

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

On slopes approaching 35 degrees and steeper, the avalanche danger is HIGH if the slope has fresh wind drifts and CONSIDERABLE it is not wind loaded. High means both human triggered and natural avalanches are likely. The danger of triggering a deeper slab avalanche in an older weak layer is greatest on northwest, north, northeast and easterly facing slopes above about 9,500 feet.

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

Mountain Weather:

A cold moist northerly flow will remain over the area through Friday. Snow showers could give the mountains an additional 3 to 6” of snow today in areas favored by northwest flow. The winds will gradually shift to the north, and should remain in the 15 to 25 mph range at most elevations. Highs today will be in the low 20’s at 8,000’ and the low teens at 10,000’. Tonight will be cold, with lows near 10 and moderate northerly winds. A ridge of high pressure will start to move in Saturday for drier conditions, with significant warming Sunday and Monday.

General Information:

Wasatch Powderbird Guides will 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 Friday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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