Wasatch Cache National Forest

In partnership with: The Friends of the Utah Avalanche Center, Utah Department of Public Safety Division of Comprehensive Emergency Management, Salt Lake County, and Utah State Parks

 

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Avalanche advisory

saturday, DECEMBER 13, 2003   9:00 am

 

SPECIAL UPDATE at 9:00 am

 

Good morning, this is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Saturday, December 13th 2003, and it’s 7:30 a.m. 

 

Current Conditions:

In late breaking news, this morning as I was issuing the avalanche advisory, we experienced rime in the mountains above about 8,500’, which put a thin crust over all our nice powder.  There may be areas with breakable crust this morning, especially at upper elevation west facing slopes.  Rime is that stuff that makes your hair frosted in cloudy conditions in the mountains.  This morning, ridge top temperatures are in the mid 20’s, which is about 10 degrees warmer than yesterday morning.  Ridge top winds have been building overnight and are now blowing 20 mph from the west and there has been just a trace to an inch of new snow overnight, and this morning a rime crust formed, ruining our nice snow in many areas.  Yesterday, the snow surface was a delightful 4-8 inches of extremely light powder on top of supportable spongy base on the north through east facing slopes   And the increasingly warm and windy weather should build to a crescendo by mid day Sunday in advance of a cold front on Sunday night.     Click here for the photo of the day.

 

Avalanche Conditions:

Although the snow remains mostly stable in all areas, for the past several days, we have mentioned the possibility of triggering some of the old wind slabs from Tuesday’s wind.  And sure enough, yesterday, avalanche control work with explosives on the Park City side of the range pulled out a couple of these old wind slabs on northeast facing slopes around 9,500’.  Both were sizable avalanches, 1-2 feet deep and 200 feet wide, running on old crusts in obviously heavily wind loaded, steep slopes.  Both required a large wallop, though—six pound air blasts in both cases and I’m not sure if a skier or sledder could have triggered these.  I think the main avalanche concern today will be the latest round of fresh wind drifts from the increasing winds and warmer temperatures.  You will probably find some localized shallow, soft wind slabs along the upper elevation ridges and they could be quite sensitive because they will sit on top of the very light density snow and some surface hoar.  Watch out for smooth, rounded snow that feels “slabby” (harder snow on top with softer snow underneath) and often sounds hollow. 

 

Bottom Line (Salt Lake, Park City, Ogden and Provo area mountains):

There is a MODERATE danger of human triggered avalanches today on any slope with recent deposits of wind drifted snow steeper than about 35 degrees.   Otherwise, the avalanche danger is mostly LOW.

 

Mountain Weather:

As a warm front pushes into Utah today, the temperatures will continue to rise and the wind will continue to blow harder and blow around 25 mph from the west on the exposed ridges.  Ridge top temperatures and wind should peak around mid day Sunday with temperatures around 30 degrees with 30-40 mph winds from the southwest.  Today we should have partly to mostly cloudy skies and a few spits of snow with accumulations around 1-3 inches.  Then, the main storm should arrive on Sunday night with a strong cold front and a quick-hitting 6-12 inches of snow with lingering snow showers on Monday.  Ridge top temperatures on Monday should drop down around 5 degrees.  For the extended forecast, it looks like nice weather through the rest of the week with perhaps another storm to freshen things up again next Saturday.

 

 

3-Day Table

3-Day Graph

7-Day Table

Ogden Mountains

Ogden Mountains

Ogden Mountains

SLC Mountains

SLC Mountains

SLC Mountains

Provo Mountains

Provo Mountains

Provo Mountains

 

For specific digital forecasts for selected mountain areas from the National Weather Service, click the links below or choose your own specific location at the National Weather Service Digital Forecast Page:

 

General Information:

We’re giving two free avalanche awareness talks next week – one on Tuesday, the 16th, at the Salt Lake REI and the second on Thursday, the 18th, at the Sandy REI.  Both start at 7pm.

 

If you are getting into the backcountry, please give us a call and let us know what you’re seeing, especially if you trigger an avalanche.  You can leave a message at 524-5304 or 1-800-662-4140.  Or you can e-mail an observation to [email protected] .org, or you can fax an observation to 801-524-6301.

 

The Friends of the Utah Avalanche Center is offering two 3-day avalanche workshops which are being held January 17-19 and February 14-16.  Information and sign-up sheets are available at the Black Diamond store (2092 E. 3900 S.; 278-0233).

 

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. 

 

Drew Hardesty will update this advisory on Sunday morning.

Thanks for calling.

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For more detailed weather information go to our Mountain Weather Advisory

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

http://www.avalanche.org/usdanger.htm