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

Tuesday, February 11, 2003

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To see a list of recent avalanches, CLICK HERE, (Updated 2-11-03)

Good Morning. This is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Tuesday, February 11, 2003, and it’s 7:30 in the morning. The Banff Film Festival is coming to Kingsbury Hall this week, February 12^th and 13^th, with different films each night. The Friends of the Utah Avalanche Center benefits from this event. Tickets are available at Kingsbury Hall, Art-Tix, the Outdoor Rec Program and REI, or call 581-8516 for information.

Current Conditions:

It was a bit blustery yesterday in the upper elevation wind exposed areas with steady 30 mph winds gusting to 40 on the highest peaks with winds more like 20 mph on some of the mid elevation ridges. People are reporting some wind damage in above tree line wind exposed areas and sun crusts on south facing slopes, but still some nice powder in the wind and sun sheltered slopes. Today may be the last day for good powder because I’m expecting the ridge top temperatures to rise to 30 degrees today and 8,000’ temperatures to get up to around 40 this afternoon.

Avalanche Conditions:

Today is the first day in nearly two weeks that we have not heard about a significant avalanche breaking into deeper layers of weak, faceted snow. I doubt if none occurred, but it’s just that fewer people were out yesterday and I haven’t heard about them. I did, however, hear about a couple of people who were able to intentionally trigger wind slabs deposited by the strong winds yesterday. On person was kicking cornices along the ridge line in Alexander Basin and triggered a wind slab in what we call “Depth Hoar Bowl” 1-1 ½ feet deep and 75 feet wide, which ran to the bottom with a nice dust cloud. Another person in the Provo-area backcountry near Sundance resort was able to intentionally trigger several similar wind slabs about 8 inches deep and 40 feet wide. The strong winds created these wind slabs by drifting snow onto lee, or downwind, terrain. Today, you will find localized wind slabs you could trigger on most upper elevation, wind exposed ridges. They will look smooth and rounded and range from being soft to very hard and they often sound hollow, like a drum. As always, you should avoid any steep slope with recent deposits of wind drifted snow.

Also, some of these wind slabs could easily overload the deeper layers of weak faceted snow that were formed during the dry spell in January, now buried about two feet deep. Almost all of the avalanches we have had for the past two weeks have been breaking on this layer.

Although there’s only localized places where you can trigger these deeper avalanches, they will be large and very scary. (If you need any convincing, you can check out the extensive photo gallery on the web at the usual site (www.avalanche.org/~uac/photos_02-03.htm). And look at the current list of avalanches at: www.avalanche.org/~uac/Avalanche_List.htm)

Finally, today at lower elevations, temperatures will be rising above freezing for the first time in over a week and you will probably see some localized damp sluffs as cold, dry snow warms up for the first time, especially below about 8,000’.

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

There is a MODERATE danger of human triggered avalanches on any steep slope with recent deposits of wind drifted snow. (Moderate in Ogden) There is also a MODERATE danger of triggering an avalanche into deeper weak layers on any slope 35 degrees or steeper that faces the north half of the compass, plus east facing slopes that are above about 9,000 feet especially on shallow, rocky snowpacks. There is also a MODERATE danger of damp sluffs at lower elevations that are warming up above freezing. If you’re looking for LOW danger terrain, you should stay out of wind affected terrain, on slopes less steep than 30 degrees.

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

Mountain Weather:

We have a beautiful clear day today with dramatically warming temperatures and we should see some increasing high clouds this afternoon and tonight in advance of our next weather system. Today, ridge top winds will diminish from 30 mph down to around 10 mph and switch from northwest to southwest. Ridge top temperatures will dramatically warm up to around 30 degrees this afternoon and down at 8,000’, the temperatures will rise to around 40 degrees. For the extended forecast, we have a closed low pressure system in California, which will pump lots of warm, moist air into Utah and give us some snow starting on Wednesday night and get more serious on Thursday and Friday. This should put some heavier, denser snow on top of all our light, dry powder snow, making upside-down snow and may significantly increase the avalanche danger

General Information:

Today, Wasatch Powderbird Guides will fly in the American Fork drainage and White Pine and they may also fly in Silver, Days, Cardiff and Mineral.

We will be giving a free avalanche awareness talk at Milo Sport on Wednesday, February 12^th at 7:00 pm. They are on 3300 South and 3119 East.

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.

Park City: Tomorrow, Craig Gordon will give an avalanche awareness talk at 7:00 pm especially for snowmobilers in Heber at Neilson’s Fast Track, which is at 1740 South on the main highway.

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.

I will update this advisory by 7:30 on Tuesday 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