Good afternoon, this is Sue Burak with the Inyo National Forest with a
   backcountry avalanche advisory and weather forecast for Thursday
   afternoon, Dec. 25, 2008.

   SPECIAL ANNOUNCEMENT AN AVALANCHE WARNING IS IN EFFECT FOR THE EAST
   SLOPES OF THE SIERRA FROM SONORA PASS SOUTH TO MT WHITNEY. OVER A FOOT
   OF NEW SNOW HAS FALLEN AT THE HIGHER ELEVATIONS. 2 FEET HAVE FALLEN IN
   THE MAMMOTH AREA.HUMAN TRIGGERED AND SNOWMOBILE TRIGGERED AVALANCHES
   ARE LIKELY.

   WINDLOADED SLOPES ARE DANGEROUS BECAUSE NEW SNOW MAY OVERLOAD THE
   EXISTING WEAK SNOWPACK. BACKCOUNTRY TRAVEL IN AVALANCHE TERRAIN IS NOT
   RECOMMENDED. DUE TO CONTINUING SNOW AND WINID TONIGHT, THE AVALANCHE
   DANGER WILL REMAIN HIGH FOR THE NEXT 24 HOURS

   MOUNTAIN WEATHER

   Winter storm warnings expire later this afternoon- however, scattered
   snow showers will stick around tonight and much of the day tomorrow.
   Another round of moderate snow is expected tonight in the mountains.
   Strong wind gusts and average wind speeds are diminishing from 60 mph
   with 120+ mph gusts on exposed ridgetops.

   Friday will be partly cloudy in areas east of the Crest and expect
   cloud and wind in the mountains. The storm track shifts north into the
   Pacific Northwest for the next week, and the only chance for
   precipitation will occur if the jet sags far enough south to affect our
   weather. Temperatures will slowly warm over the next 5 days.

   SNOWPACK AND AVALANCHE DISCUSSION

   Primary avalanche concern: storm snow. The area around Mammoth and
   north have received several feet of snow and 2-3 inches of water in the
   last 24 hours. South of Mammoth, 1-2 ft of snow has fallen. Snow and
   wind will continue into this evening. The very weak snowpack we had on
   the ground prior to this event will most likely not be able to support
   the load of storm and wind transported snow. Natural avalanches are
   likely. Wind loaded slopes steeper than 35 degrees are primed for
   natural avalanches, especially since in wind prone areas, the new wind
   slabs are higher density than much of the pre-existing snow.

   Winds during the storm were mainly from the southwest to south.
   However, The Tioga area experienced winds from the southeast and east
   which would load slopes facing west and to the northwest. All slopes
   with wind loaded snow are likely to avalanche with the added mass of a
   skier or snowmobile. Avalanches will release naturally as well as with
   human triggers.

   BOTTOM LINE

   The avalanche danger is HIGH this afternoon and will remain HIGH for 24
   hours. Natural avalanches are expected and human triggered slides are
   likely. Fresh wind drifts at all elevations could produce avalanches.
   Backcountry travel in avalanche terrain is not recommended. Extensive
   skill, experience and local knowledge are essential.

   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.