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.

 

AVALANCHE ADVISORY

Monday, March 20, 2006  7:30 am
Good morning, this is Drew Hardesty with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Monday, March 20, 2006, and it’s about 7:30 am. 

 

Current Conditions:

Skies are partly to mostly cloudy this morning with the mountains picking up only an additional inch or two overnight.  Bruce’s analogy of the swirling brontosaurus is difficult to forget, and seems once again apropos for this exiting storm system.   The winds remained light and variable during the event while 1-2’ of snow fell in the higher terrain.  Temperatures are in the upper single digits and mid-teens.  Except for the sunny aspects, riding conditions are sweet.

 

Recent Avalanche Activity & Snowpack Discussion:

High snowfall rates produced a localized shallow natural cycle in the higher terrain on a variety of aspects in the Tri-Canyons yesterday, with most 1’ deep and less than 100’ wide.  The cycle wrapped up in the mid a.m., but travelers prodded many more into moving with cornice drops and ski cuts as the stability was on the rise.  By the afternoon, heating dampened many south facing slopes, resulting in at least one healthy unintentionally triggered wet sluff in mid-Big Cottonwood Canyon. 

 

Things were much more interesting in Provo, at least on the north side of Provo Canyon.  Saturday’s light rain/precipitating slush up to about 9500’ produced a facet/crust layer due to what we call melt layer recrystallization.  As you may recall from Avalanche 101 (or turn to page 128 in your textbooks – or check out our encyclopedia for faceting.), the freezing process jacks the metamorphism into overdrive, faceting the grains just above and below the newly formed crust.  Now we have a crust (bed surface), faceted snow (weak layer), a slab (new storm snow), and whallah-just like that, a field day with both remote and sympathetically triggered avalanches.  Most (another photo) were 8-12” deep and some up to 200’ wide, and often triggered up to 200’ away.  (See also ‘remote’ and ‘sympathetic’ triggers in the encyclopedia.)

 

Due to time, settlement, and warming temperatures, many, but not all, of the instabilities in the snowpack of the central and northern Wasatch will have healed.  You could trigger many soft slabs at will yesterday, but today they’ll be more stubborn, pockety and much less widely distributed.    Safe travel protocol and the usual combat techniques in the backcountry will still be required.   

 

Bottom Line:

A MODERATE danger with the storm snow will linger on through today in the steepest terrain that received the most snow.  Naturals are not expected and the instabilities of yesterday will be much more stubborn and pockety.  If the sun comes out for any amount of time, watch for the danger of wet activity to jump to MODERATE on all sun exposed slopes.  If the southwesterly winds pick up earlier than expected, watch for a batch of freshly blown wind drifts along the lee of ridgelines and breakovers.

 

Mountain Weather:

Intermittent snow showers will follow in the wake of the exiting storm system off to the east.  Brief ridging will develop this afternoon ahead of the next weakening storm system due to arrive tonight into tomorrow.  Winds today will generally be light and variable with mountain temps in the upper teens to upper twenties.  We’ll have mostly to partly cloudy skies and maybe an additional accumulation of an inch or so.  The southwest winds should pick up into the 20mph range later this afternoon.  Tuesday’s storm looks like a 4-7” event with high pressure set for the remainder of the week.  The next system moves through late in the weekend.

 

Announcements:
Here is a great link to a web site on avalanche beacon information, created by a person who did independent research and testing of avalanche beacons.
http://beaconreviews.com

Early birds and snow geeks can catch our 6AM report at 364-1591.

Click here to check out our new online avalanche encyclopedia.

Click HERE for a text only version of the avalanche advisory.

To have this advisory automatically e-mailed to you each day, click HERE.

UDOT also has a highway avalanche control work hotline for Big Cottonwood, Little Cottonwood, and Provo canyons, which is updated as needed. 801-975-4838.

The Wasatch Powderbird Guides didn’t get out yesterday and if they can fly today will be in AF-out through White Pine, and will trade for a Tri-canyon permit to be in Silver, Days, Cardiff, and Grizzly Gulch.  For more info, call 742-2800.

Please report any backcountry snow and avalanche conditions.  Call (801) 524-5304 or 1-800-662-4140, email uac@avalanche.org or fax 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.

Brett Kobernik will update this advisory by 7:30 Tuesday morning.  Thanks for calling.