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

 

: http://www.avalanche.org/~uac/

 

Avalanche advisory

Saturday, NOVEMBER 14, 2003†† 7:30 am

 

Good morning, this is Bruce Tremper with the Forest Service Utah Avalanche Center with your avalanche and mountain weather advisory.Today is Saturday, November 15, 2003, and itís 7:30 a.m.

 

Current Conditions:

With just a trace of new snow last night and yesterday, storm totals are around 15 inches in the past couple days and around two feet in the past week.Settled snow depths range are 2-4 feet and the coverage is getting pretty goodYesterdayís freezing level was around 6,000í with damp snow below about 8,000í and fairly light and fluffy snow at upper elevations.With partly cloudy skies overnight the temperature dropped to 18 degrees at 8,000í and on the ridge tops itís blowing 5-15 mph from the southwest and temperatures are around 20 degrees.

 

Avalanche Conditions:

Backcountry skiers triggered 9 different avalanches I know of yesterday in the backcountry, some intentional and some unintentional.There were yet three more in the East Bowl of Silver Fork, One on Rocky Point near Alta, one at Alta, which is not yet open for the season and is not doing any avalanche control and four in the McConkies Bowl in a closed area of Park City, which the skiers had to ski out of the moving slides.I have more details on these slides on our more detailed recorded information line at 364-1591 and I will also post a list and photos on the web at www.avalanche.org, click on Salt Lake and then on Advisories.All these avalanches fractured on the weak layer of frost or ďsurface hoarĒ that formed on the surface of the snow last weekend, then two storms with wind this past week piled on a couple feet of new snow, which became the slab.Most of the slides are a couple feet deep and 50-100 feet wide.In Utah, because we live in such a dry climate, we usually donít get many avalanches on surface hoar, which is lucky since itís undoubtedly the trickiest weak layer on the planet.Itís very thin and hard to see in a snow pit wall and itís very pockety, meaning that it might exist on one slope, and not on the next.Also, itís very persistent, avalanches tend to occur in very unusual places and even on slopes as gentle as 32 degrees.Most of the problem seems to be above about 9,000 feet on northerly through easterly facing slopes but we donít have a very good handle on the pattern distribution.It seems to be a bit of a crap shoot.Until this layer of surface hoar adjusts to its load, you will need to assume each slope is guilty until proven innocent.Play it conservative and stick to slopes under about 32 degrees. ††If you must push slope angles today, do lotís of digging in the snow and do stress tests to look for the characteristic clean, spring-loaded shears on a thin layer of sparkly feather-like crystals.

 

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

The avalanche danger is CONSIDERABLE today on slopes facing the north through east quadrants of the compass, above about 9,000í, and steeper than about 34 degrees. Considerable means that human triggered avalanches are likely.There is a MODERATE danger on south facing slopes and all slopes less than about 34 degrees.

 

Mountain Weather:

We have several storm pulses crossing our area in the near future with a weak system this morning, then another one tonight and yet another one on Sunday.These might add 3 inches today, 3-6 more inches tonight and few more inches on Sunday.Ridge top winds will blow today from the southwest 10-15 mph and become stronger on Sunday and turn northwesterly.Ridge top temperatures will remain in the mid 20ís and down at 8,000í the high today should be near 30 with the overnight low in the mid 20ís.The extended forecast calls for another storm on about Thursday and then becoming cold with another storm by next weekend.

 

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:

 

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

 

 

General Information:

Starting on Monday, Alta Ski Area will be closed to uphill traffic because of avalanche control and slope preparation for their opening on Thursday.

 

If you are getting into the backcountry, please give us a call and let us know what youíre 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 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 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