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

 

Monday, March 17, 2003

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Good Morning.This is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.Today is Monday, March 17, 2003, and itís 7:30 in the morning.

 

Current Conditions:

This morning the snow is beginning to fall again and Iím expecting snow showers through the day.Winds are out of the north and they have picked up to around 20 mph with stronger gusts, and ridge top temperatures are in the mid teens with temperatures in the mid 20ís to just below freezing down around 7 to 8,000í.Yesterday, the sun sneaking through the thin clouds made mashed potatoes out of the new snow and put a bit of a crust on all slopes except the straight north facing ones, where you can still find a foot of dense powder snow this morning in the Salt Lake area mountains.The storm Friday and Saturday night added about a foot of dense snow to the Cottonwood Canyons and Park City with about an inch and a half of water weight.The Ogden and Provo area mountains got about 5 inches with less than an inch of water weight.The Logan area mountains got almost no snow.

 

Avalanche Conditions:

Yesterday, there were at least six human triggered avalanches in the backcountry.All of them were soft slab avalanches in higher elevations of the Cottonwood Canyons about a foot deep and ranging from 50 to 100 feet wide on slopes approaching 40 degrees or steeper, on slopes facing the north half of the compass.All were above 9,500í in elevation and most, but not all, were near ridge lines on slopes that got heavy wind drifting from Saturdayís strong south winds.Yesterday, there was also an attention-grabbing deep hard-slab avalanche in the backcountry east of Brighton triggered remotely from an explosive inside of the Brighton Resort.It broke 3-5 feet deep and 300 feet wide and it fractured on the weak faceted snow near the ground.This was an example of the steep, thin snowpack areas that we have been talking about for most of the season and it was the third time this particular slide path has run this season.I have details on these slides in the usual locations at 801-364-1591 and at www.avalanche.org Ė click on Salt Lake, then on Advisories, then on List of Avalanches).

 

Yesterday, the avalanche conditions were extremely elevation dependent with wet snow and localized wet sluffs and wet slabs below about 9,000í and dry soft slabs and localized hard slab avalanches above about 9,500í.Iím thinking that the new snow is so warm and dense that the soft slab instability will settle out quickly and today there will be much more localized places where you can still trigger avalanches.

 

Bottom Line (SLC, Park City Area Mountains)

Today there is low end of MODERATE danger of human triggered soft and hard slab dry avalanches above 9,500í, mostly on slopes that face the north half of the compass, plus east facing slopes.If, by some chance, we get more than about 8 inches of new snow today or if the winds become strong, you can expect the danger to rise to CONSIDERABLE on steep slopes with recent wind drifts.

 

Bottom Line: (Ogden and Provo Area Mountains): MODERATE danger on steep slopes with recent wind drifting today.

 

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

 

Mountain Weather:

We have unusual weather today with a very large, closed low pressure system that covers most of the Rocky Mountain States and itís centered nearly on top of us.Itís kind of like a brontosaurus doing the whirling dervish and weíre standing just in between its legs.Everything around us is getting blasted but as long as youíre in the middle, you are in the eye of the storm and nothing happens.But this morning the brontosaurus is moving to the east and things may get interesting.Today our ridge top winds will blow from the north and become stronger.This should give us snow showers most of the day.Itís such an odd storm, Iím not sure what is going to happen, but I think weíll get about 3-6 inches of snow in the upper elevations with the rain-snow line around 6,000í.Ridge top winds should blow from the north around 20 mph with stronger gusts.Ridge top temperatures should be in the mid 20ís with 8,000í temperatures just under freezing.This storm should continue to produce clouds and snow showers on Tuesday with ridge top winds becoming northeasterly with lingering clouds and showers on Wednesday as well.

 

General Information:

As a special treat the more scientifically inclined avalanche nerds out there, our own Ethan Greene will be giving a more advanced-level avalanche talk at REI tomorrow night called the ďscience of avalanches.ĒThis will be at 7:00 pm at REI, which is on 3300 south just off the 215 east side belt route.

 

Wasatch Powderbird Guides will probably 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.

 

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