Outdoors

Avalanche advisory: Two weak layers to consider

WINTER SPORTS — The region's mountain snowpack is stabilizing, but snow-goers must be aware of a couple of weak layers, says Kevin Davis in the Idaho Panhandle Avalanche Center weekly avalanche advisory issued this morning.

Of the two layers of surface hoar, one has been buried for just over a week and has stabilized, but continue to watch it on northerly aspects, he said. The other just got buried on Wednesday.  Its not under enough snow to be a problem yet, although in the Cabinets it might be in places, but it could be a problem in the future, he said.

An avalanche workshop is being presented tonight,  6 p.m. at the Forest Service Building in Sandpoint. The Avalanche Center staff will review 10 years of avalanche accidents in North Idaho.

February and March are the most common months for human triggered avalanches.

Read on for the complete avalanche advisory.

 

 

 

AVALANCHE ADVISORY

 

U.S. FOREST SERVICE

FORECASTER:  Davis

IDAHO PANHANDLE AVALANCHE CENTER

EFFECTIVE DATE:  02/10/2012

DATE ISSUED:     02/10/2012  0730

OUTLOOK:  02/11-12/2012

This report does not apply to local ski areas within the forecast region and the hazard rating will remain valid through midnight February 10th, 2012.  Special thanks to Idaho Parks and recreation for sponsoring this Avalanche advisory.   

Thanks to everyone for sending in pit data this week.  Had a report of a human triggered slide in the Selkirks last Friday north of Jeru.  Check out our new site @ idahopanhandleavalanche.org.

WEATHER

TODAY:  An 80% chance of a few inches of snow across our forecast region.  Temperatures will be on the warm side and approaching balmy to the south, Lookout Pass at 32 degrees at 6AM.  Winds light.

TONIGHT:  1-2 inches of snowfall expected with temperatures hovering around freezing to the south, high 20s to the north.  East winds to the north, south winds to the south.

SATURDAY:  Chance of snow decreases for the weekend and the temperatures remain mild, and winds pick up slightly from the west.  The outlook for Saturday and Sunday calls for mostly cloudy conditions with a 50% chance of less than an inch of new snow.  Temperatures in the low 30s.  This weather will tend to settle the snowpack.  The avalanche danger will decrease for the outlook period.

Selkirks and Cabinet mountains:In the Selkirks yesterday we found 2 layers of buried surface hoar.  We got moderate shears on last weeks buried hoar that was 1 foot deep.  The 2/8/12 surface hoar layer was under 1 inch of new and not shearing under the light load but watch this layer as we accumulate new snow.  On southerly aspects it sits on top of a firm crust.  On North Baldy, west of Priest Lake, Mike found the same layering of surface hoar with moderate to hard shears on the deeper weak layer.  In the Cabinets snowfall from the last 2 days is deeper, snotel shows 7 inches, so you should probably check the upper hoar layer especially on slopes steeper than 35 degrees.  Avalanche danger is rated MODERATE on aspects steeper than 35 degrees above 5,000 feet.  Avalanche danger is rated as low on slopes less than 35 degrees.St. Regis Basin and Silver valley:  At Lookout Pass the surface snow layers were getting heavy and Carole noted loose point releases and pinwheels.  They found pockets of buried surface hoar under an inch or so of snow on north aspects.  Weak layers were mostly the result of decomposing crusts but stability tests revealed hard and dirty shears so the mild temperatures are stabilizing the pack at present.  On Moon Pass Ed found hard shears on crust layers and the newly buried surface hoar.  No major concerns for today from his observations but he said to watch that new hoar layer in the future.  On Silver Mountain, patrol dug at 6200 feet and got a hard but clean shear on a crust at 2 feet deep.  Avalanche danger is rated MODERATE on aspects steeper than 35 degrees above 5,000 feet.  Avalanche danger is rated as low on slopes less than 35 degrees.The mild weather and light snowfall have had a stabilizing effect on the weak layers in the pack.  Crusts are still weak but have gained some strength and the temperatures that weakened them last week will not be as much a concern this weekend.  Be aware that a layer of surface hoar at 1-2 feet deep has gained some strength but could still be touchy on cold N/NE aspects.  The 2/8/12 surface hoar layer could become a future problem but give it a check in the Cabinets today since it could be buried deeper there.

The next avalanche advisory will be issued February 17th.  We’ll review 10 years of avalanche accidents in North Idaho tonight at 6PM at the Forest Service Building in Sandpoint.  C’mon down.

Have a safe and pleasant weekend!!!!

Contact:  Kevin Davis (208) 265-6686, Ed Odegaard (208) 245-6209, or John Olson (208) 265-6635

This message is available by calling (208) 765-7323 or toll-free at 1-866-489-8664.

E-mail address:  kevingdavis@fs.fed.us, eodegaard@fs.fed.us,  jrolson@fs.fed.us, ebmorgan@fs.fed.us

 




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Rich Landers

Rich Landers’ Outdoors blog


Rich Landers writes and photographs stories for a wide range of outdoors coverage, including a Sunday feature section and a Thursday column. He also writes the Outdoors Blog.


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