This is Chris Lundy of the Sawtooth National Forest Avalanche Center
 with your Backcountry Avalanche Advisory and Weather Forecast for
 Monday, February 4, 2008 at 7:30 am.

 Bottom Line:
 Today the avalanche danger is estimated to be CONSIDERABLE. Facet
 layers buried 18-24 inches deep were responsible for natural and
 triggered slides yesterday as well as collapsing, cracking, and poor
 stability test scores. Most sunny aspects have a facet/crust layer
 beneath the recent storm snow and these slopes are showing the poorest
 stability. On shady, northerly facing slopes of our northern
 mountains, the buried facet layers are not as pronounced and these
 slopes are estimated to have a MODERATE danger.

 Heads up: Periods of sunshine today will result in solar warming of
 the snowpack, exacerbating our stability problems especially on
 southerly aspects.

 Primary Avalanche Concern:
 
 
 
 
 Faceted snow that formed during the mid-January dry spell was buried
 by the heavy snowfall over the past week. This layer is now buried
 18-24 inches deep throughout our region, except in areas loaded by
 recent winds where it may be found much deeper. Yesterday was an
 active day in the backcountry, with natural and triggered slides and
 reports of poor stability in most areas.

 In the South and Central Valley, these facet layers are widespread but
 seem to be most problematic where the snowpack remains shallow such as
 at low to mid elevations. A group on Triple Peak in Lake Creek
 yesterday reported a rumbling collapse that seemed to cross at least
 one of the bowls. This collapse was initiated near where I dug on
 Saturday and found very poor stability.

 In the North Valley, areas with a shallow and weak snowpack are less
 common, but an incident yesterday reminds us of their presence. A
 group was skiing below Timber Bowl on the backside of Titus Ridge and
 triggered a large slide while crossing a gully. They crossed the slope
 one at a time, but an avalanche released about 2 feet deep right as
 the last skier reached the safe point. Unfortunately his dog was
 caught in the slide and buried. The group searched for an hour with
 probes and finally heard some whimpering beneath the snow. Despite
 being buried 4 feet deep, the dog was found alive. One of the skiers
 reported that the snowpack in this location was shallow and that he
 could feel facets beneath the newer snow when we stuck his pole in.

 Perhaps the worst stability in our region is on sunny, southerly
 facing slopes where a crust with facets above it is buried 18-24
 inches deep. I was in Anderson Creek yesterday where two pits on
 southerly aspects gave me the heeby-jeebies. My second pit was the
 most interesting, because after getting unremarkable results from
 Compression and Extended Column Tests, I received a large collapse
 while cutting out a Rutschblock and a crack shot out 30 feet from the
 pit and opened about an inch. Just another reminder that stability
 tests can occasionally be frighteningly inaccurate. However, the
 Rutschblock failed very cleanly on one jump (see video,
 http://www.youtube.com/watch?v=mZrtO41BqkU ). Backcountry skiers
 reported collapsing and cracking on a south aspect above Titus Lake,
 and another group near Prairie Creek reported poor stability test
 scores on a sunny slope. A natural avalanche occurred on an
 east-southeast aspect above the highway at the top of Galena Summit,
 and I suspect many of you have heard that a large avalanche released
 just before noon yesterday on the southeast facing slope above Penny
 Lake and buried Warm Springs Road (see photo).

 Northerly aspects in our northern mountains appear to have better
 stability but dont take this as a green light. There is a lot going on
 in our snowpack right now and each slope should be evaluated
 carefully. Periods of sunshine yesterday warmed the snowpack, and
 probably caused the Penny Lake slide. More solar warming is likely
 today, and this will cause greater instability on any slope receiving
 sunshine. However you wont find me on or under any southerly facing
 slope steeper than 30 degrees whether the suns shining or not.

 Current Conditions:
 Despite cold ambient temperatures yesterday, periods of sunshine
 midday resulted in significant warming on sun exposed slopes. In the
 afternoon, clouds returned and we picked up about 1-2 inches of new
 snow with the passage of a weak cold front. With the front, winds
 shifted to the north and blew 10-20 mph through the night. Mountain
 temperatures this morning are in the single digits, and its 11 degrees
 in Ketchum.

 Mountain Weather Forecast:
 A northerly flow over our region will keep temperatures on the cool
 side today, but I expect partly cloudy skies will lead to periods of
 warm February sunshine. Mountain highs are expected to reach the mid
 to upper teens, and temperatures should hit the mid 20s in the valley.

 Ridgeline winds will continue from the north-northwest at 10-20 mph.