INTRODUCTION:
   This is Tony Willits with the backcountry avalanche advisory issued by
   the U.S. Forest Service Glacier Country Avalanche Center at 8:00 AM,
   Friday, January 18th for the Glacier Park and Flathead and Kootenai
   National Forest areas.
   HAZARD ANALYSIS
   Between 5500 and 7500 feet of elevation the avalanche danger is
   currently being rated as CONSIDERABLE, especially on wind loaded
   terrain. Below 5500 feet of elevation the avalanche danger is
   currently being rated as MODERATE.
   These danger ratings expire at midnight, Friday, January 18th.  The
   outlook is for the avalanche danger to possibly elevate if predicted
   winds materialize on Saturday.
   Because of the general nature of this advisory message, each
   backcountry party will always need to make their own time and site
   specific avalanche hazard evaluations.
   WEATHER ANALYSIS:
   Temperatures have chilled since Tuesday from our seasonable January
   temperatures to single digits on Wednesday and then rebounding to the
   mid teens on Thursday.  Snow accumulations were spotty across the
   region since Tuesday's advisory.  A slim line of storm activity
   dropped significant snow across the Southern Whitefish Divide and into
   the Noisy Basin area, where 1.3 inches of snow water equivalent was
   gained in a 24 hour period.  Other sites that received moderate
   amounts and were more over the Middle Fork and Marias Pass locations.
     The Southern Missions and the Cabinets received only light amounts
   of snow accumulation.   Winds were significant across the region on
   Tuesday, creating wind loading and slabby conditions on buffeted
   terrain.  Winds did ebb into Thursday in valley locations along the
   Middle Fork but were still strong at ridge tops with prevailing winds
   from the southwest.

   SNOWPACK ANALYSIS:
   Our backcountry observations Thursday were from Canyon Creek drainage
   on the Flathead National Forest, Bear Mountain in the West Cabinets on
   the Kootenai National Forest and the Marias Pass area in Glacier
   National Park.
   The new snow accumulations were spotty, although evidence of wind
   action was not, especially at the upper elevations.  The cold
   temperatures have preserved instabilities in the top 50 to 60 cms of
   the snowpack .  Some solar warming may have effected the near surface
   layer in some locations which may have created at least a weak surface
   crust.  Clean and crisp shears were experienced within the upper 60
   cms of the snowpack and will be present for the next several days with
   the prediction of colder temperatures.

   AVALANCHE - INSTABILITY DESCRIPTION:
   <>Between 5500 and 7500 feet in elevation we are currently rating the
   avalanche danger as CONSIDERABLE ...unstable slab layers are
   probable on steep terrain, especially on wind loaded terrain. Natural
   avalanches are possible, while human triggered avalanches are
   probable. Backcountry travelers should be very cautious in steeper
   terrain. Be aware of potentially dangerous areas of unstable snow.<>

   Below 5500 feet of elevation the avalanche danger is currently being
   rated as MODERATE...unstable slab layers are possible on steep
   terrain. Natural avalanches are unlikely, while human triggered
   avalanches are possible. Backcountry travelers should use caution in
   steeper terrain on certain aspects.
   WEATHER FORECAST & AVALANCHE OUTLOOK:
   `
   A northerly flow will continue to bring light snow to most locations
   into Friday.  By Friday night moisture associated with an upper level
   low pressure trough will begin to bring additional snow to the
   region.  The trough will move into the Northern Rockies Saturday
   bringing more snow, wind and much colder temperatures.

   The early December melt freeze layer should continue to warrant
   concern on how it influences its immediate adjacent interface
   especially on more shallow snowpacks.  This would most likely occur on
   southerly aspects. On northerly aspects and at upper elevations this
   melt freeze layer may become more deeply buried and more faint but
   this doesn't disregard weak interfaces preserved by the colder
   temperatures that we are currently experiencing. Wind loaded terrain,
   will be the watch word in the coming days.  This is due to the cold
   temperatures preserving weakness in the bonding surfaces that they
   overlay and with the likelihood of new snow and strong winds expected
   in the next few days  This maybe more pronounced in the Middle Fork
   area but will certainly have affects on westerly and southwestern
   slopes across our region late Saturday and early Sunday as the trough
   moves into our region.  Site specific pit observations will be
   necessary not only with changing aspects but maybe elevationally
   especially on southerly aspects.
   Please note that this avalanche advisory is our best interpretation of
   snow pack conditions and National Weather Service forecasts on the day
   the advisory is issued. Unanticipated weather changes such as wind, a
   marked temperature increase, or precipitation beyond forecast amounts
   can increase the avalanche danger. Local variations may also exist.
   The next avalanche advisory will be on Tuesday, January 22nd, 2008.