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

 

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Avalanche advisory

Monday, FEBRUARY 18, 2002  3:30 pM

 

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Good afternoon, this is Evelyn Lees with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Monday, February 18, 2002, and it’s 3:30 p.m.

 

Current Conditions:

The closed low is moving slowly east across southern Utah, leaving northern Utah with only light snow.   So far, the Cottonwoods have received 1 to 4”, with other areas reporting mostly a trace to an inch.  Winds shifted to the northwest around noon, and speeds have started to increase.  Temperatures made it into the low to mid twenties, and are now dropping.  Snow surface conditions include some decent dust on supportable crust on many slopes, with soft snow on some mid elevation sheltered, shady slopes.  Shallow snow pack areas are becoming unsupportable.

                                                                                             

Avalanche Conditions:

There was an avalanche accident high on the Mary Ellen side of the American Fork Twin yesterday morning.  A skier triggered a hard slab avalanche that broke around the old January 6 ice crust.  This is the same layer that was responsible for a major avalanche cycle in late January and early February.  The slide broke about 120 feet across and 1 to 3 feet deep.  The slope was southeast facing at about 11,400 feet.  The person, an experienced avalanche worker, was injured as he was carried over a rock band.  Fortunately, it sounds like he will be OK.  This is one of the above-timberline slopes that did not avalanche during the storm on January 28 and it was also drifted by the strong winds last Thursday.  The initial slide released a second similar slab avalanche below and to the left of the first one. 

 

Today’s new snow is bonding poorly to the hard slick crusts and to weak surface snow on shady slopes.  Watch out for sluffing on steep slopes and, as the winds increase tonight, for fresh batches of shallow, but sensitive new wind drifts.

 

In the big picture, our snow pack is a frustrating layer cake of weak snow grains sandwiched between stronger slabs.  This weak faceted snow exists at a variety of levels in the snowpack, and is notorious for being persistent.  It is in these layers that there is still an isolated chance of triggering a deeper hard slab avalanche and any slides in the new snow this week may step down into these deeper weak layers.

 

While many of the current avalanche problems aren’t large in size or wide in distribution, always be thinking consequences – even a small sluff or slide on can send you off a cliff or into trees. 

 

Bottom Line: 

The danger of human triggered avalanches is LOW on most slopes.  However, there are isolated areas where it is possible to trigger an old wind slab or a more dangerous deeper hard slab, especially on steep mid and upper elevation slopes.

                                                                                                                      

(Provo Area Mountains)

Mostly the same general conditions as in the SLC mountains.

 

(Ogden Area Mountains)

Mostly the same general conditions as in the SLC mountains.

 

Mountain Weather:

Scattered light snow showers will continue tonight, with accumulations of generally a trace to as much as 3” possible in areas favored by northwest flow.  The northwesterly winds will increase to 15 to 20 mph along the ridges.  Lows tonight will be 10 to 15.  Tuesday will be mostly cloudy, with late afternoon snow showers possible.  Northwest winds 15 to 25 mph along the ridges.  Highs will be near 15 at 10,000’ and 25 at 8,000’.  The next chance for snow - Tuesday night into Wednesday - looks potentially disappointing with more wind than snow in the forecast.

 

General Information:

During the Olympics, we will issue both morning and afternoon advisories.  We’ll use the 364 -1591 line for more detailed or additional avalanche information.

 

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 uacobs@avalanche .org, or you can fax an observation to 801-524-6301.

 

Wasatch Powderbird Guides will not be flying during the Olympics. 

 

We have a new icon-based, short advisory posted each day at www.avalanche.org.  We would appreciate any feedback on this new product.

 

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 by 7:30 am Tuesday 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