Wasatch Cache National Forest
In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and Salt Lake County.

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AVALANCHE ADVISORY

Friday, January 04, 2008  11:30 am
Good morning, this is Evelyn Lees with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Friday, January 04, 2008 and it’s about 7:30 am.

Avalanche Watch:

An avalanche watch has been issued for the mountains of northern, central and southern Utah.   A prolonged storm with powerful winds and periods of heavy snowfall is expected to increase the avalanche danger in the backcountry for the weekend.  Backcountry travelers are urged to check the latest avalanche advisories for current information at Utahavalanchecenter.org or 1 888 999 4019.

 

Current Conditions:

Southerly winds began increasing yesterday ahead of a major winter storm that will impact the area through Monday.  Currently, many mountains stations have 15 to 25 mph averages, with gusts in the 50’s.  Across the highest peaks, average wind speeds are 35 to 50 mph, with “knock you off your feet” gusts to 70 mph.  Temperatures have cooled into the low 20’s at 10,000’, and near freezing at 8,000’.  Sun and wind damage have taken their toll on the snow surface, with the last of the decent settled powder tucked away on very sheltered shady slopes.

 

Avalanche Discussion:

No new avalanches were reported from the backcountry.

 

It’s all about the wind today.  While the strong winds are blowing some of the snow to Rock Springs, Wyoming and sublimating other snow grains back into water vapor (click here), much of the blowing snow will be packed into dense drifts and cornices.  Drifting will occur along some ridgelines (click here), but the high wind speeds will also create drifts at low and mid elevations.  Southeast to southwesterly winds predominately load slopes facing the north ˝ of the compass, but the high speeds will also cross load snow into unexpected places - around sub ridges, mid slope breakovers, rocks and trees.  These wind drifts and cornices will be sensitive to the weight of a person on many steep slopes, especially those with weak, surface snow, including many of the shady mid and low elevation slopes.

 

There are still concerns about isolated places where weak facets near the ground and mid pack weaknesses could be overloaded, resulting in deep slides.  Activity the past week shows shallow snowpack areas exist at a variety of aspects and elevations, not just the upper elevation northerly facing slopes.  As the day progresses, increasing winds will drift additional snow (weight) onto these slopes, and increase the potential for them to be triggered by backcountry users.

 

Bottom Line for the Ogden, Salt Lake, Park City and Provo area mountains:

There will be a rising avalanche danger today and through out the weekend.  For today, there are pockets of CONSIDERABLE avalanche danger on steep, wind drifted slopes, especially those with a shallow, weak underlying snowpack.  Other slopes steeper than about 35 degrees have a MODERATE danger.   Wind drifts will become deeper and more widespread as the day goes on, and natural avalanche are possible.  There are isolated where a deeper, larger avalanche could be triggered, especially in thinner snowpack areas.

 

Mountain Weather: 

A potent Pacific storm system with multiple fronts will move across Utah late tonight through Sunday night, and the National Weather Service has issued both High Wind Warnings and Winter Storm Warnings.  Ahead of the first front, the southerly winds are just getting warmed up this morning.  Wind speeds will gradually increase throughout the day, peaking tonight with sustained ridgeline averages of 35 to 45 mph, with gusts in the 70’s.   Across the highest peaks, averages could reach 55 mph, with gusts in the 90’s.  Skies will be mostly cloudy today, with temperatures remaining in the mid to upper 20’s at 10,000’ and reaching mid 30’s at 8,000’.  Snow will start falling tonight, and become widespread and locally heavy after midnight. Winds will shift to the northwest and decrease early Saturday as the cold front arrives, with extremely high snowfall rates possible.  A second cold front will arrive Sunday evening.

 

Announcements
Wasatch Powderbird Guides did not fly yesterday, and will not be flying today due to high winds.  For more information, call them at 801-742-2800.

Solitude’s beacon park is now up and running, and ready for use.  It’s FREE and located just off the northwest corner of the lower lot.

 

For an avalanche education class list, updated 12/22/07, click HERE.

If you want to get this avalanche advisory e-mailed to you daily click
HERE.

UDOT highway avalanche control work info can be found HERE or by calling
(801) 975-4838.

Our statewide tollfree line is 1-888-999-4019 (early morning, option 8).

For our classic text advisory click HERE.

If you’re getting out and see anything we should know about please let us know.  You can leave a message at
(801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 801-524-6301)

The UAC depends on contributions from users like you to support our work.  To find out more about how you can support our efforts to continue providing the avalanche forecasting and education that you expect, please visit http://www.avalanche.org/~uac/fuac-welcome.htm

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. Brett Kobernik will update this advisory by 7:30 on Saturday morning.