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Forecast for the Provo Area Mountains

Issued by Bruce Tremper for
Tuesday, December 18, 2012

With a very complex pre-existing snowpack, complex wind yesterday and complex new snow patterns overnight...yep, you guessed it, we have a complex avalanche situation. Today you'll find lots of large booby traps waiting for a human trigger. Stay off of, and out from underneath, all slopes 30 degrees or steeper that face northwest, north, northeast and east above about 9,000'. All other slopes, treat with suspicion. If you are a skier or boarder, this would be a good day to head to one of our world-class resorts. If you're a snowmobiler, this would be a good day to stay on the trails and gentler slopes. Don't be fooled by the powder on the surface and the solid feel of the underlying snow.

Low
Moderate
Considerable
High
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Avalanche Warning

An avalanche warning is in effect for the mountains of northern Utah. Strong wind and new snow have overloaded weak, pre-existing snow. This has created the potential for dangerous, human triggered avalanches and occasional natural avalanches. Backcountry travelers should stay off of, and out from underneath, slopes steeper than about 30 degrees.

Special Announcements

Discount lift tickets are in! With a wild week of weather and backcountry avalanches in the forecast, heading to one of our world class resorts is a great idea. Go to http://www.backcountry.com/utah-avalanche-center to get tickets from our partners at Alta, Beaver Mountain, Brighton, Canyons, Deer Valley, Park City, Powder Mountain, Snowbasin, Snowbird, Solitude, Sundance, and Wolf Mountain. All proceeds benefit the Utah Avalanche Center. A big thanks to the Utah mountain resorts - we couldn't do it without your partnership.

Weather and Snow

The winds yesterday afternoon made blizzard conditions and closed lifts, blowing 40 mph, gusting to 70 from the west, which blew all our great powder into dense, wind-board. Overnight, the winds died down dramatically after the cold front passed and In the Cottonwood Canyons, 8 inches of snow fell overnight with 16 inches at Brighton and the snow is 8-10% water weight. The Uinta Mountains had over a foot of snow with 1.4 inches of water weight. Yesterday the Logan area mountains had 16 inches of snow with 1.8 water weight

Recent Avalanches

Yesterday, not too many people were out but someone witnessed a natural avalanche in McDonold Draw along the Park City ridge line. There was also a couple naturals in the afternoon in upper Little Cottonwood Canon in upper elevation, north facing, unopened, un-skied terrain 3' deep and a couple hundred feet wide. Avalanche control results from resorts had one large, deep slide in Little Cottonwood Canyon 5' deep, 100' wide to the ground on a cross-loaded, west facing slope around 10,500'. The Ogden area reported some large avalanches on their upper mountain with control work.

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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description

We have monsters in the basement. The pre-exisitng snow is a real junk show with extremely variable patterns. I'm most frightened of a layer of faceted snow buried in the middle of the snowpack, which produced several natural and explosive-triggered avalanches yesterday. UAC intern Trent Meisenheimer has a great video summary and one of our observers, Michael Janulaitus has a great snow profile. It's now buried under two harder layers so it's the old low probability - high consequence situation--difficult to trigger but if you do, it will make a large avalanche with a fracture depth of 2-5 feet.

This layer exists mostly on the upper elevation, shady aspects--northwest, north, northeast and east facing slopes above about 9,000' but occasionally extending down to 8,000' in very sun-shaded areas.

Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description

The very strong wind yesterday afternoon created stiff wind drifts on most aspects and elevations. They would crack easily yesterday but they will be much more stubborn today. They will be difficult to see because the new snow has covered them up.

Avalanche Problem #3
New Snow
Type
Location
Likelihood
Size
Description

Finally, the new snow that fell overnight may sluff on the steep slopes and there may be occasional soft slabs. The main danger with the new snow is that it's what we call "sucker snow", which suckers people into riding in terrain where they shouldn't. The powder will ride great, the underlying, hard wind slabs will feel solid...until everything breaks out several feet deep.

Additional Information

The storm is mostly over with the frontal snow band sinking into central Utah. We should have a few more light snow showers this morning in the southern Wasatch Range. Ridge top winds should blow 10 mph from the north with ridge top temperatures in the teens and it will drop to near zero overnight. Skies should be cloudy today but should clear out by Wednesday.

The extended forecast calls for a few rest days coming up with warmer temperatures and clear skies.

General Announcements

Go to http://www.backcountry.com/utah-avalanche-center to get tickets from our partners at Ala, Beaver Mountain, Brighton, Canyons, Deer Valley, Park City, Powder Mountain, Snowbasin, Snowbird, Solitude, Sundance, and Wolf Mountain. All proceeds benefit the Utah Avalanche Center.

If you trigger an avalanche in the backcountry - especially if you are adjacent to a ski area – please call the following teams to alert them to the slide and whether anyone is missing or not. Rescue teams can be exposed to significant hazard when responding to avalanches, and do not want to do so when unneeded. Thanks.

Salt Lake and Park City – Alta Central (801-742-2033), Canyons Resort Dispatch (435-615-3322)

Ogden – Snowbasin Patrol Dispatch (801-620-1017)

Powder Mountain Ski Patrol Dispatch (801-745-3773 ex 123)

Provo – Sundance Patrol Dispatch (801-223-4150)

Dawn Patrol Forecast Hotline, updated by 05:30: 888-999-4019 option 8.

Twitter Updates for your mobile phone - DETAILS

Daily observations are frequently posted by 10 pm each evening.

Subscribe to the daily avalanche advisory e-mail click HERE.

UDOT canyon closures UDOT at (801) 975-4838

Wasatch Powderbird Guides does daily updates about where they'll be operating on this blog http://powderbird.blogspot.com/ .

Remember your information can save lives. If you see anything we should know about, please participate in the creation of our own community avalanche advisory bysubmitting snow and avalanche conditions. You can also call us at 801-524-5304 or 800-662-4140, or email by clicking HERE

Donate to your favorite non-profit –The Friends of the Utah Avalanche Center. The UAC depends on contributions from users like you to support our work.

For a print version of this advisory click HERE.

This advisory is produced by the U.S. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist. Specific terrain and route finding decisions should always be based on skills learned in a field-based avalanche class.

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