Wasatch Cache National Forest

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Avalanche advisory

THURSDAY, MARCH 21, 2002 07:30 AM

 

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Good morning, this is Tom Kimbrough with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Thursday, March 21, 2002, and it’s 7:30 a.m.

 

Current Conditions:

Yesterday was the first day of spring but today will feel like the first day of summer!  This morning temperatures are already 10 degrees warmer than at this time yesterday, now in the upper twenties and low thirties.  Winds are light from the southwest.  Snow surfaces are widely crusted this morning, with a little settled powder on upper elevation north facing slopes.

 

Avalanche Conditions:

I went sightseeing around the Wasatch yesterday, looking at some of the numerous large avalanches that have cut loose over the past week.  It was a rather sobering trip.  Some of the slides, especially those triggered yesterday by backcountry explosive testing, are awesome.  They would have smashed a person like a giant fly swatter.  On Wednesday morning, backcountry explosive testing produced several very large avalanches.  The entire upper bowl of Mineral Fork avalanched, as well as the East Fork of Mineral Fork, Red Baldy in White Pine Canyon and an 800 foot wide avalanche between Red and White Baldy.  These slides broke at least 4 feet deep, probably down to the January rain crust.  The testing team said they broke very wide and popped right out, indicating that a person could have easily triggered them.  Another slide from control work broke into old snow near Sundance in the Provo mountains.  There were also some wet slides yesterday, one of which almost reached the Little Cottonwood road.  We also got a report of a slide on the north slope of the Uintas that buried a snowmobiler to his shoulders on Tuesday.

 

With temperatures getting into the forties and fifties today, we will see more wet surface slide activity today, especially on east, south and west facing slopes as the snow begins to heat up.  I am also worried that today’s warming could make some of the deep weak layers even more sensitive.  Bob Athey, looking at the Mineral Fork slides from Gobblers yesterday, said he wouldn’t go near Mill B or Broads today.  They have snow packs similar to Mineral Fork and I wouldn’t bet my life that today’s heating won’t bring down some natural avalanches in those drainages and perhaps others as well.  Most of the reported avalanche activity over the past week has been in the Salt Lake area mountains.  Not much has been reported from the Uintas and Provo but from what I know of the snow pack in those areas, I suspect that conditions are similar or even worse.  In these conditions, snow pits, slope cuts and other stability tests don’t tell you much.  Other than knowing that a specific slope has recently avalanched deeply, I don’t think there is a sure way to tell if a steep slope is likely to break on you.

 

There will be some high clouds today that may increase the effect of the warm air temperatures on slopes not receiving direct sun.  This could increase the avalanche danger even on north facing slopes.

 

Given the increasingly crusted slopes in the backcountry and the current Russian Roulette avalanche conditions, I am inclined to go biking until we get more snow or some corn snow develops.  If you are getting into the backcountry today, avoid slopes steeper than about 35 degrees that have not recently had deep avalanche activity.  I would also stay out of avalanche run-out areas as the day warms up.  As we start to move into warmer weather, remember the springtime rules:  Get out early and head home or at least get off of and out from under steep slopes as the snow starts to get wet and mushy. 

 

Bottom Line: 

The danger of triggering a very large and deadly avalanche is localized or MODERATE this morning but will rise to CONSIDERABLE as the day begins to warm.  The danger could become HIGH, with natural avalanches likely, as temperatures soar this afternoon.  While slopes receiving direct sun will be the most active, the danger will increase in all areas as temperatures rise.

 

(Provo Area Mountains)

Same as Salt Lake Mountains.  

 

(Western Uinta Mountains)

The avalanche danger in the Western Uintas is CONSIDERABLE.  Very large and dangerous human triggered and natural avalanches are possible on steep slopes. 

 

(Ogden Area Mountains)

MODERATE increasing to CONSIDERABLE.

 

Mountain Weather:

Today will be partly sunny with variable high clouds.  Winds will be 5 to 15 mph over the ridges from the southwest.  High temperatures today will be in the 50’s at 8,000 feet and near 40 degrees at 10,000.  Weather conditions will be similar on Friday but with increasing southwest winds in the afternoon.  The weekend looks like a return to stormy weather. 

 

General Information:

Wasatch Powderbird Guides will be flying in Cardiff, Days and Silver and Mineral Forks today with a home run in Grizzly Gulch.  For more information call 521-6040 ext. 5280.

 

To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, you can leave a message at (801) 524-5304 or 1-800-662-4140.  Or you can e-mail an observation to [email protected], 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. 

 

I will update this advisory by 7:30 on Friday morning.

Thanks for calling!

________________________________________________________________________

  

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