ZCZC SLCWRKSNW TTAA00 KSLC 052306 Good afternoon, this is Tom Kimbrough with the Forest Service, Utah Avalanche Forecast Center with your avalanche and mountain weather bulletin for the Salt Lake area mountains. Today is Thursday, December 5 at 3:30 p.m. This bulletin is brought to you in part by a generous donation from The North Face, makers of technical clothing for the avid outdoor enthusiast. The mountain snowfall has a little slow to get going today but a cold front arrived here at the airport at 11:00 with plenty of snow and now the mountains are getting an inch an hour or more. Before the arrival of the front, the wind was really howling; up to 90 mph on Mt Ogden. Speeds have dropped some since noon and are now blowing a slightly more reasonable 20 to 30 mph over the high ridges. Avalanche control work produced spotty results this morning when there wasn't much new snow but still plenty of wind. The largest and most sensitive slides I have heard of were on the east side of the range. One was 300 feet wide, 1 to 2 feet deep and ran long. This was a 35 degree, east facing slope at about 10,000 feet. Today's activity has so far been within the new and wind blown snow. Now with the increased snowfall the avalanche conditions are becoming more sensitive. We are issuing and avalanche warning for all of the Wasatch Mountains. The danger of human triggered avalanches is high and could reach extreme in some areas. Spontaneous avalanches are possible. This weather system is unusual in that the cold front is oriented almost east-west, parallel to the strong jet. This could mean that the front stays over us for a longer period resulting in impressive storm totals. There are several impulses visible on the satellite pictures that may also help. Temperatures will cool slowly into the teens, again because the front is not likely to push rapidly to the south. A winter storm warning remains in effect for the Wasatch mountains. We will have snow, heavy at times this afternoon and tonight and perhaps continuing into Friday morning. As for accumulations .....most places should be getting close to a foot now. If the front remains stalled over northern Utah, the Ogden mountains and the Cottonwoods could get another foot or more tonight and Friday. The Park City side and the Provo mountains could get closer to 18 inches. Ogden-Logan: We are issuing an avalanche warning for the Wasatch mountains. The Ogden mountains are getting particularly hard hit by this storm. With a weak snow pack and very heavy snowfall rates, all slopes steeper than 30 degrees are likely to be sensitive to the weight of a person. Spontaneous avalanches are quite possible. Slopes may be triggered from near-by low angle terrain. Avoid steep slopes and avalanche run-out areas. There are two distinct avalanche problems to consider as this storm increases the load on the snowpack. First and most obvious is the new snow and the drifting effects of the strong wind. Expect these smooth and rounded newly deposited wind drifts to be sensitive to the weight of a person on slopes approaching 35 degrees and steeper especially above 9,000 feet on easterly facing slopes. Cracking and collapsing will be clues to the instability. The second and perhaps more subtle problem is associated with the deeper layers. There are several layers of faceted snow and also nasty buried rain crusts below this week's new snow. As weight from new and wind drifted snow accumulate these deeper layers are likely to become sensitive again. The faceted layers are considerably worse at lower elevations, below about 9,000 feet and also outside of the Cottonwood Canyons in the Logan, Ogden and Provo mountains and at the lower elevations on the Park City side. Deeper and more widespread avalanches will be possible in these areas. Trail breaking will be very difficult on Friday and most slopes that are steep enough to make turns on will also be steep enough to slide. People without advanced route finding and snow stability skills should avoid the backcountry. The storm should taper off later on Friday. The weekend looks nice. For up to date information on road conditions in Little Cottonwood canyon tune your radio to 530 on your AM dial. This coming week is Avalanche Awareness Week. Unfortunately, the class especially for snowmobilers at Plaza cycle for this weekend has been canceled due to lack of interest. But there's no lack of interest with skiers and snowboarders. This weekend there will also be a fun race at Solitude which includes running gates with and finding a beacon for prizes. That will be noon on Saturday at Solitude. Then on Sunday there will be a beacon clinic just for snowboarders between 10:00 am and 2:00 pm at Silver Lake which is between Solitude and Brighton. Finally there will be a social get-together at the S.L. roasting Co on Sunday night starting around 6:00 pm. Logan: Basic Avy Class Dec. 11 & 14. Dec 11 lecture session 6:00 pm to 10:00 pm at Biology bldg. #314. Dec 14 field session 8:00 am all day. fee $ 30. Register at LAFC at Natural Resource bldg # 233 or by phone at 97-0457 To report avalanche activity and snow conditions give us a call and leave a message on our answering machine. Our office number is 524-5304. You can also call that number if you want a list of avalanche classes taught this season. Finally, you can get that information along with this bulletin and a detailed mountain weather forecast on the Internet at www.avalanche.org. Remember that because this bulletin covers a wide geographic area it offers only generalized avalanche information. Local variations always occur and the ultimate responsibility for your own safety lies in your personal routefinding and snow stability decisions. The Utah Avalanche Center is brought to you by the Forest Service in partnership with the National Weather Service, the State of Utah, Salt Lake County and the Friends of the Utah Avalanche Forecast Center. I will update this bulletin by 7:30 on Friday morning. Thanks for calling. Kimbrough