Good morning, this is Sue Burak with the Eastern Sierra Avalanche
   Center with an avalanche advisory posted on Monday, April 21, 2008.

   Special Announcement

   MOUNTAIN WEATHER

   After 3 days of wind, cold and no snowfall today will be a few degrees
   warmer with only breezy winds. Under a flat high pressure ridge this
   morning, skies are mostly clear and 7 AM temperatures are in the mid
   teens. After a very brief respite, a spring storm moves into the
   northern and central Sierra bringing a 50% chance of snow for tomorrow
   night and Wednesday. Forecasters at the Reno NWS office say this storm
   will produce the best snowfall since early March.

   Tuesday will be partly cloudy with another couple of degrees of warming
   but temperatures fall again on Wednesday with highs in the low 30s at
   the 9,000 ft elevation. Thursday should be the beginning of a few days
   of warming temperatures for a good weekend for spring skiing and
   riding.

   By tomorrow afternoon, a low pressure system moves into the area
   bringing a 50% chance of precipitation. A 50% chance of precipitation
   usually means a few inches of snow on Mammoth Mountain and elevations
   above 10,000 ft in Mono County.

   SNOWPACK AND AVALANCHE DISCUSSION

   A cold air mass and strong winds offset late April solar radiation and
   snow surfaces above 9,000 ft remained firm over the weekend. Terrain
   steeper than about 25 degrees did not soften much at all, though spring
   skiing was great after about 11AM below 9500 ft. With a few inches of
   snow forecasted, there might be enough snow to fill in the valleys
   between the ridges of fins that are forming and making skiing
   unpleasant, especially when the snow surface doesnt soften with the
   suns energy.

   Snowpit profiles are similar on west, south and east aspects above
   9,000 ft. There is a knife hard ice layer that ranges from 3 to 5
   inches thick. Underneath is a disturbing moist layer that can be up to
   a meter deep. This is moist, fine grained faceted snow that you can
   stick your fingers. There are globs of ice in this layer; a sign that
   surface melt was beginning to make its way down to the bottom of the
   pack, probably during the warm temperatures and clear skies of a
   weekend ago. Reports from the back side of the Palisades, Mather Pass
   and Taboose Pass indicate similar snowpack layering and firm skiing
   conditions over the weekend. Once spring finally arrives in the high
   country, the snowpack layering could become a serious problem. As long
   as the weather remains winter like, with little surface melting, the
   avalanche danger rating remains LOW. This could change by Thursday if 6
   inches or more of snowfall occurs with the upcoming storm.

   BOTTOM LINE
   The avalanche danger rating today is LOW.

   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.