Utah Avalanche Bulletin
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This bulletin is from the UAC, which is part of the US Forest Service.
Utah Avalanche Center (UAC) Advisory 
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The information in this advisory is from the US Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
Keywords:
;
avalanche danger;
cold front;
corn snow ;
faceted;
high pressure;
human triggered;
natural avalanche;
naturals;
powder ;
slab;
sluffing;
sluffs;
weak layer;
weak layers;
wind drifts;
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Wednesday, March 17th 2010
Current Conditions:
Under clear skies, temperatures are in distinct thermal layers this morning, with the lower elevations in the Park City and Salt Lake mountains in the 20's and still cooling, while temperatures at the higher elevation have flat lined in the 32 to 35 degree range.
The northerly winds are just strong enough to slightly cool the snow surface, in the 5 to 15 mph range. It is a real mix of snow conditions, with the best bets for fun riding the band of corn snow on mid elevation southerly through westerly facing slopes, and the limited windblown thick powder on mid to upper elevation northerly facing slopes.
Recent Activity:
I just received a report of a scary, big, wet slab natural avalanche that released on an east facing slope in the Aspen Grove area of the Provo mountains yesterday afternoon. Other than that, the only activity reported yesterday was a few wet, loose naturals, many initiating at rock bands, and the snow sliding off several more roofs in mountains towns.
Today will be a balancing act - but hopefully the increasing high clouds of varying thickness and light, but consistent winds will keep the wet avalanche issues from getting entirely out of hand. Still, there is a full smorgasbord of heat related avalanche issues to watch out for today, and how they play out will depend on your exact location.
·Wet loose sluffs will rapidly become easy to trigger on steep sunny slopes. Naturals may occur.
·Roof-a-lanches - avoid travel below steep, snow covered roofs that will continue to shed their snow.
·Cornices are very sensitive and breaking back further than expected.
·Greenhousing, caused by the high thin clouds, could heat the snow on low and mid elevation shady slopes, allowing for wet, loose sluffing.
·Glide avalanches - are the least manageable of all the heat related problems, are large and dangerous . Reduce the problem by careful route finding to minimizing your time beneath suspect slopes, which are most common in Broads, Mill B South and Stairs Gulch, sub-drainages of mid-Big Cottonwood Canyon.
Remember - if you're in a place with lots of direct sun and dead calm winds, the snow will heat quickly and avalanche danger rapidly increase.
The buried, faceted weak layers are slowly strengthening, but in isolated places it is still be possible to trigger a slide 1 to 2' deep on this weak layer. They are most widespread in the mid-elevations of Big Cottonwood Canyon, Mill Creek and Lambs.
Bottom Line:
Salt Lake and Park City area mountains:
The avalanche danger will rapidly rise to for wet, loose
avalanches. Natural avalanches are possible, and human triggered slides
likely, on steep, sunny slopes as the day heats up. Avoid travel on and
below steep east through south through west facing sunlit slopes once
the snow becomes damp and sloppy and all steep, lower elevation slopes.
Spring conditions dictate early starts and early finishes. Pockets of
danger remain for lingering weaknesses in the northerly
mid-elevation slopes and for a few old wind drifts.
Mountain Weather:
The ridge of high pressure will hold for one more day, continuing the warm temperatures, with 8,000' highs in the low 50's and 10,000' highs in the mid 30's. Thin clouds will increase this afternoon, and the northerly winds will be light, in the 5 to 15 mph range. The Thursday/Friday storm will come in two pieces - a cold front Thursday afternoon could bring a few inches of snow, with lightening possible.
The second, colder portion of the storm Thursday night into Friday could produce an additional 4 to 8" of snow. Then it's back to toasty warm temperatures through the weekend, with another chance for snow around Tuesday.
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The USFS posts some additional information through the season:
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