This is Chris Lundy of the Sawtooth National Forest Avalanche Center
 with your Backcountry Avalanche Advisory and Weather Forecast for
 Sunday, December 30, 2007 at 7:30 am.

 The Twin Falls District Bureau of Land Management & the Friends of the
 Sawtooth Avalanche Center bring you this advisory.

 Bottom Line:
 Today the avalanche danger is estimated to be CONSIDERABLE on
 steep, wind loaded slopes. On slopes unaffected by the wind the
 avalanche danger is estimated to be MODERATE. Todays strong winds
 will likely create sensitive wind slabs in a variety of terrain
 features, especially in our northern area where more snow is available
 for transport.

 On non wind loaded slopes, it is still possible to trigger a slide in
 pockets of weak, sugary snow existing primarily in shallow areas,
 steep and rocky terrain, or in the high alpine.

 In our far northern and western mountains where more recent snow has
 fallen, it may be possible to trigger a soft surface slab around a
 foot deep.

 Primary Avalanche Concern:
 
 
 
 
 The primary factor affecting todays avalanche conditions is the wind.

 Westerly winds were quite strong yesterday and are forecasted to
 increase significantly today. This wind event will likely reach down
 into lower elevation terrain as well.

 In our northern mountains, more recent snowfall means plenty of fluffy
 snow that will be easily transported by the strong winds. With the
 nature of this wind event, the formation of wind slabs may not be
 isolated to the ridge crests, and you may find pockets of drifted snow
 on lower terrain features and in unusual places.

 In the South and Central Valley, there is less snow available for
 transport so fresh wind slabs will be more isolated and pockety in
 nature. However, the snowpack in this region is weaker overall, and
 any wind slab that forms over weak, sugary snow will be very suspect.

 Secondary Avalanche Concern:
 
 
 
 
 There are many locations in our northern mountains where the snowpack
 is deeper and relatively strong, but pockets of weaker snow still
 remain throughout our area where it remains possible to trigger a
 slide.

 In the North Valley, Salmon Headwaters, and Sawtooth regions these
 weaker areas can be found in steep and rocky terrain, in areas where
 the snowpack remains less than about 3 feet deep, and in high alpine
 areas. Their isolated nature means you are less likely to find a weak
 spot, but the flip side is that they are harder to predict. In these
 locations, it remains possible to trigger a slide 1-3 feet in depth.

 Your best bet remains evaluating each steep slope carefully and
 sticking to more uniform terrain and deeper snowpack areas.

 In the South and Central Valleys, the snowpack is much shallower and
 consequently weaker, but there is not much of a slab sitting on top of
 it. The exception is where past wind events or todays wind has created
 a slab atop the weak, sugary snow.

 Heads up for the Western Smokies and Sawtooths:
 These regions have picked up significantly more snow over the past two
 days upwards of a foot in some places. We have seen some evidence of a
 poor bond within the recent storm snow and it may be possible to
 trigger shallow surface slabs in steeper terrain.

 Current Conditions:
 Since yesterday morning, the mountains around Ketchum received 1-2
 inches of new snow, Galena Summit picked up about 2-4 inches, and in
 the far northern and western areas including the Salmon Headwaters and
 Sawtooth Mountains, around 6-8 inches of snow has fallen.

 Winds at 10,000 feet averaged 15-25 mph yesterday, blowing generally
 from the west. Theyve picked up this morning and are currently blowing
 at 25-35 mph with gusts into the 40s and 50s. Mountain temperatures
 this morning are in the low teens.

 Mountain Weather Forecast:
 Todays storm will be more blow than snow as a very strong
 northwesterly jet dips into our region. Still, we can hope to pick up
 2-4 inches of new snow by tomorrow, with a bit more possible in our
 far western and northern mountains. But the real story is the wind,
 which is forecasted to blow 20-30 mph along upper elevation ridgelines
 with much stronger gusts likely. I would expect the wind to also reach
 down into the lower elevations and valley bottoms. Mountain
 temperatures will probably not warm much from their current values,
 meaning that highs will be in the low to mid teens. The valley should
 reach about 20 degrees.