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, February 13, 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 Thursday, February 13, 2003, and it’s 7:30 in the morning.

Tonight is the last night of the Banff Film Festival at Kingsbury Hall, with a different set of films. Tickets are available at Kingsbury Hall, Art-Tix, the Outdoor Rec Program and REI, or call 581-8516 for information. The Friends of the Utah Avalanche Center benefits from this event.

Current Conditions:

Today you can leave the down parka at home, but if you’re planning to spend much time below 8,000’ you might want to pack a rain coat. With overnight lows near 30 degrees at 8,000’, temperatures this morning are 3 to 8 degrees warmer than yesterday. The winds have been from the southwest and less than 10 mph in the valley bottoms. Along the highest ridgelines the winds have been in the 15 to 25 mph range most of the night. The thin cloud cover deepened overnight and precipitation began early this morning. Presently there is a trace of new snow and the rain/snow line appears to be around 8,000’.

Over the last few days the snow surface has been battered by wind, sun, and warm temperatures. Yesterday temperatures climbed into the mid 40’s at 8,000’ and the snow surface on sun exposed slopes became quite damp. Fortunately the surface snow remains soft in areas above about 8,500’ that are sheltered from the wind and sun.

Avalanche Conditions:

Yesterday while traveling in exposed areas I found hard wind slabs along the lees sides of the ridgelines. These wind slabs were formed by wind and warm temperatures over the past few days. In many areas they are sitting on very weak faceted snow and sound hollow as you move across them. Although I was only able to elicit minor cracking in these hard layers, they could be very dangerous if you get one to slide. The most likely place to trigger one of these wind slabs is on a very steep rocky slope that typically has a shallow snowpack or in an area that has avalanche earlier in the year.

Today looks like the last day of are warming trend, but unfortunately the precipitation began before the cold air got here. We are getting reports of mist and drizzle this morning with a trace of new snow above 8,000’. On northerly aspects the surface snow is quite weak and many not hold much of new load. The new snow should be quite dense and we could see sluffing on steep shady slopes as it piles up. I only expect a few inches to fall during the day, but if enough new snow falls to form a slab soft slab avalanches will be likely.

Both wind slab avalanche and new snow avalanches have the potential to step down into deeper layers on steep northwest through east facing slopes above about 9,000’.

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

Today there is a MODERATE danger of human triggered avalanches on any steep slope with recent deposits of wind drifted snow. There is also a MODERATE danger of triggering an avalanche into deeper weak layers on northwest, north, northeast and easterly facing slopes, steeper than about 35 degrees and above about 9,000 feet.

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

Mountain Weather:

The closed low off the cost of California is beginning to open up and move eastward. Today moist southwest flow ahead of this system will bring warm temperatures and dizzily precipitation to the Wasatch Mountains. Temperatures will rise into the upper 30’s at 8,000’ and upper 20’s at 10,000’. The wind will shift from the southwest to the west during the day. Along the higher ridgelines wind speeds will be in the 25 mph range through mid afternoon. The rain/snow line should be around 8,000’ for most of the day and dropping to 7,000’ overnight. The new snow should be fairly thick, but I expect 2 to 4 inches to accumulate during the day.

General Information:

Wasatch Powderbird Guides will not be flying today.

The Friends of the Utah Avalanche Center are offering an intensive three-day avalanche class February 15 – 17. A generous donation by Voile and Milosport helps make this class affordable at $125. To sign up call the Black Diamond retail store at 801-278-0233.

To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, remember that the information you have could save someone’s life. 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.

Tom Kimbrough will update this advisory by 7:30 on Friday 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