Good morning, this is Sue Burak with the Inyo National Forest with an
   avalanche advisory for Saturday, December 27, 2008. 
   MOUNTAIN WEATHER

   Mostly sunny skies will prevail over the weekend. After a frigid
   morning with lows in the single digits or below zero in most mountain
   locations, temperatures will crawl upwards 5-10 degrees F today with
   highs around 18 at elevations above 10,000 ft. Mid elevations will warm
   up to 25F. Expect the winds above 10,000 ft to continue gusty from the
   north. Lower elevations will see west winds today as high pressure
   becomes centered in the eastern Pacific. Sunday will be 5 degrees
   warmer then temperatures moderate for Monday. Lows will warm up 10
   degrees also. Sunday will be breezy with west wind gusts up to 30 mph.

   SNOWPACK AND AVALANCHE DISCUSSION

   Storm totals range from 5 feet on Mammoth Mountain to less than 20 in
   the southern Sierra. Winds were strong enough during the 24 -36 hours
   of the storm to transport large amounts of snow onto the wind protected
   sides of slopes. Fridays north winds created wind slabs on usually
   safer south and west facing terrain. A number of natural slides
   occurred today off the Mammoth Crest and hand charging off the top of
   Mammoth produced a 12 ft crown that ran on the rain layer we have been
   seeing in the middle of the depth hoar, weak snow at the base of the
   pack.

   Don't let the lure of new snow and improved skiing and riding
   conditions drive you to make hasty and careless decisions. Previous to
   this storm, the snowpack was shallow and very weak at the base. Many
   people reported settlement and shooting cracks. It is important to be
   aware that this problem probably won't improve as quickly as we would
   like it to, especially if temperatures remain unseasonably cold.

   BOTTOM LINE

   The avalanche danger rating for today is CONSIDERABLE in wind loaded
   terrain above tree line. You will find unstable slabs in steep wind
   loaded terrain. This means north facing slopes greater than 35 degrees
   and includes the top of the Sherwin Bowls, many lines off the Mammoth
   Crest and the Negatives. In areas where there was a snowpack before
   this storm, there is 3-4 feet of wind affected snow sitting on top of
   the old snowpack which is sitting on top of very weak snow. The
   snowpack needs more time to stabilize. Use conservative decision
   making, careful route finding and good travel habits.

   The avalanche danger rating for today in mid elevation trees is
   MODERATE on slopes steeper than 35 degrees. MODERATE which is not a
   green light because dangerous avalanche conditions exist on some
   terrain features such as the wind loaded sides of gullies and convex
   rolls at the top of glades. The outlook for Sunday is for similar
   avalanche conditions as clear cold weather continues.

   Please note that the avalanche danger rating in this advisory expires
   in 24 hours. This advisory is our best interpretation of snow pack
   conditions and NWS forecasts issued today. Backcountry travelers should
   be aware that elevation and geographic distinctions are approximate and
   that a transition zone exists between upper and lower elevations.

   Avalanches do not happen by accident and most human involvement is a
   matter of choice not chance. Most avalanche accidents are caused by
   slab avalanches that are triggered by the victim of member of the
   victim's party. Even small slides can be dangerous. Always practice
   route finding skills and carry avalanche rescue gear. Remember that
   avalanche danger ratings are only general guidelines. Distinctions
   between geographic areas, elevations, slope aspects and slope angles
   should be made.