This is Matt Lutz of the Sawtooth National Forest Avalanche Center
 with your Backcountry Avalanche Advisory and Weather Forecast for
 Wednesday, January 30, 2008 at 7:30 am.

 Blaine County Search and Rescue & the Friends of the Sawtooth
 Avalanche Center bring you this advisory.

 Special Announcement:
 This is Avalanche Awareness Week. See the Friends of the Avalanche
 Center link http://www.sawtoothavalanche.com/friends.php for a
 complete schedule.

 The Best of Banff Film Festival and SNFAC Fundraiser is this Thursday,
 Friday, and Saturday at the NexStage Theater in Ketchum.

 Film Trailer:
 http://ca.youtube.com/watch?v=xeBYLLYnd_I&feature=related
 Film List: http://www.sawtoothavalanche.com/banff_film_list.doc
 Bottom Line:
 Today the avalanche danger in the South Valley, Central Valley and
 Soldier Mountain area is estimated to be CONSIDERABLE. Sundays
 storm deposited approximately 1.5 to 2 feet on new snow onto a very
 weak old snow surface. Mondays widespread natural avalanche cycle was
 clear evidence of unstable snow and more time is needed for the snow
 in these areas to stabilize.

 The avalanche danger in the North Valley, Smoky Mountains, and
 Sawtooth Mountains is estimated to be CONSIDERABLE on wind loaded
 slopes. The recent storm deposited approximately 2 feet of new snow in
 our northern terrain. Reports suggest that a natural avalanche cycle
 occurred primarily on wind loaded southern aspects and ran significant
 distances.

 Human triggered avalanches are possible today. Today the two main
 potential failure layers of concern are a density change within the
 new snow and the old snow/new snow interface. And lets not forget
 about those deeper facet layers that we have been running on about all
 season. Sticking to low angle sheltered terrain and staying out of run
 out zones is a good idea.

 Primary Avalanche Concern:
 
 
 
 
 Sundays storm snow combined with strong winds on Monday provided for a
 very active natural avalanche cycle. There was a density increase
 during the second half of the storm. This density increase was the
 primary culprit for most of the avalanche activity in the South and
 Central Valley. Adding to the instability were the winds during and
 after the storm. During the storm the wind was primarily out of the
 southeast. As the storm tapered off on Monday morning the wind shifted
 to the west northwest. East and southeast aspects have the greatest
 amount of storm snow and recent wind slabs.

 We have received rather limited observations from our northern
 terrain. What we have heard indicates that the density change in the
 storm snow combined with the wind loading caused a cycle in the
 northern terrain as well. This cycle does not appear to have been
 nearly as widespread as the South and Central Valley, but a slide was
 reported on a south aspect off of Senate Peak that ran approximately
 2000 vertical feet.

 Secondary Avalanche Concern:
 
 
 
 
 Ah, the faceted layers. These layers remain a concern throughout our
 forecast area, but depending on where you go the patterns of these
 layers are different. Prior to this last storm our forecast area had
 widespread small grained faceted snow at the snow surface. This old
 snow/new snow interface was responsible for a portion of the natural
 cycle observed on Monday. This is especially the case in our southern
 terrain. The new snow/old snow interface is between 1.5 to 2 feet
 deep.

 A second rather widespread facet layer is found on solar aspects
 throughout our terrain. This layer consists of a lamination of sun
 crusts with near surface faceted layers sandwiched in between. This
 crust layer was within the top 6 to 10 inches of the old snow and is
 now buried about 2.5 feet deep.

 Deeper faceted shear layers are becoming less prevalent but are still
 a concern to me. These layers are harder to pin point and require
 slope by slope detective work to identify. I still feel the need to
 dig my snow pits rather deep so I can look for these layers. I am
 primarily looking for weak large grained faceted snow layers that
 indicated a structural deficiency within the deep snow.

 Current Conditions:
 Ketchum is currently under partly cloudy skies with a temperature
 hovering right around zero. Upper elevation winds are light out of the
 west northwest with occasional moderate gusts. Upper elevation
 temperatures are in the low single digits. Winds are forecast to
 increase into the moderate range through the day.

 Nice soft snow riding conditions can be found in sheltered terrain on
 most all aspects. Exposed terrain at mid to high elevation got fairly
 torn up by Mondays wind.

 Mountain Weather Forecast:
 Today expect partly cloudy to mostly cloudy skies with the chance of
 occasional snow showers. Today snow totals will be around 1 inch.

 Ridge top winds are forecast to be out of the northwest in the 20 mile
 per hour range. Valley temperatures should be between 16 to 26 degrees
 and ridge top temperatures between 5 to 10 degrees. Another strong
 storm is forecast to move into our area on Thursday and Thursday
 night. Heavy snows accompanied by moderate to strong winds are
 expected with the next storm.