The Eastern Sierra Avalanche Center is issuing a Backcountry Avalanche
   Warning for the eastern slopes of the Sierra Nevada from Mt. Whitney
   to Sonora Pass. Strong winds combined with new snow containing a large
   amount of water has elevated the avalanche danger rating to HIGH on
   all slopes above 7,000 ft. The snowpack is very unstable and natural
   and human triggered avalanches are likely. Avalanche terrain including
   avalanche runout zones should be avoided.

   MOUNTAIN WEATHER
   A winter storm warning is in effect through 10 AM Monday morning.
   Moderate to heavy snowfall will continue through tonight and tomorrow
   morning. A cold front has reached northern California and should reach
   Mono and Inyo counties by early tomorrow morning. The heaviest
   snowfall will move east by mid morning, though elevations above 9,000
   ft will continue to have light snow and snow showers. Up to 4 feet of
   snow is possible by Monday morning.

   Temperatures today have been in the upper 20s above 8,500 ft. Lows
   tonight will be in the mid teens as a result of the cold front passing
   through. Monday will be much colder with highs around 15F. Strong
   southwest and southeast winds are blowing in the 40-60 mph range with
   the highest wind speeds on the top of Warren exceeding 100 mph.

   The Tuesday storm may be more of a Tahoe event but snow showers are
   expected above 9,000 ft in Mono County.

   SNOWPACK AND AVALANCHE DISCUSSION
   Heavy snowfall and strong winds have created significant avalanche
   concerns. Temperatures warmed a few degrees earlier today, then
   cooled, creating a reactive layer within the new snow that shows up in
   stuffblock and extended column tests. There is a definite change in
   snow grain type and size at about 15-20 cm down from the surface. The
   boundary between yesterdays and todays snow surface is also weak and
   easily releases with stuffblock and extended column tests. Ski cutting
   by patrol is showing 12 crowns.

   Though wind speeds are high and consistent in direction at the top of
   Mammoth and Mt. Warren, other wind sensors show erratic wind
   directions. This means wind loading is occurring on all aspects. Winds
   that have transported snow onto previously wind loaded areas have
   created a significant amount of stress that could overload the
   snowpack and trigger avalanches that break into older snow.

   Precipitation rates over the last 10-12 hours range from 0.1 inch an
   hour to over 0.3 inches per hour. The January 4-7 storm had
   precipitation rates of 0.3 to 0.4 inches an hour and there was an
   extensive avalanche cycle. In this case, past performance is a good
   indicator of future performance.

   BOTTOM LINE
   Strong winds combined with new snow containing a large amount of water
   has elevated the avalanche danger rating to HIGH on all slopes above
   7,000 ft. The snowpack is very unstable and natural and human
   triggered avalanches are likely. Avalanche terrain including avalanche
   runout zones should be avoided.

   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.