Good morning, this is Sue Burak with the Eastern Sierra Avalanche
   Center. Today is Thursday January 10, 2008. We apologize for getting
   this advisory out late. We are having server problems.

   I will be giving a talk on Climate Change and the Sierra snowpack this
   Friday evening at 6 PM. We meet at the Mammoth Community Water
   District conference room at 6 PM. This event is free.

   MOUNTAIN WEATHER
   Mostly cloudy skies and snow showers are expected today as a storm
   passes to the north. Daytime highs will be in the mid 30s above 9,000
   feet with higher elevations reaching the upper 20s. West northwest
   winds are ramping up this morning with gusts over 30 mph on the top of
   Mammoth and 40-50 mph on Mt. Warren. Expect strong winds today above
   10,000 feet with gusts to 60 mph and 70 mph. Lower elevations (9,000
   feet) have southwest winds 20-30 mph with gusts around 40 mph.

   The cloudy skies and scattered snow showers continue through Saturday.
   Ridging moves into the Eastern Sierra on Sunday for a possibly
   extended period of dry weather. However, this mornings Reno NWS
   discussion used the MJO word for next week. This could mean a return
   to very wet weather. However, only one model shows the MJO influence
   on West coast weather. More reliable information will be available by
   the end of the weekend.

   SNOWPACK AND AVALANCHE DISCUSSION
   Snow and strong winds in the last and the persistent depth hoar layer
   in the last 48 hours prevent the danger level from dropping to
   moderate on north to east aspects in alpine terrain. Predominant wind
   direction in the last 24 hours has been southwest with some winds from
   the northwest. With west northwest winds at higher elevations this
   morning, look out for cross loading in north facing gullies.

   Wind speeds are more than enough to move a lot of snow- wind speeds of
   15 mph will transport snow. It is a calm day when the top of Mammoth
   has 15 mph winds, so 30-40 mph winds today are a big heads up in the
   Bardinis, the Lakes Basin and the Convict area. The Rock Creek Road is
   not plowed, so access into the higher elevations requires a 6-8 mile
   tour. The avalanche danger rating today is MODERATE with area of
   CONSIDERABLE in steep wind loaded terrain from the Mammoth Basin to
   Bishop Creek.

   In addition to wind loading, the other avalanche concern is the depth
   hoar layer at the base of the snowpack. This layer is reactive in a
   wide range of elevations and aspects. Lower elevation slopes from
   7,000 to 8,500 ft have a MODERATE danger rating. The lower elevations
   have a well formed 3 to 6 inch depth hoar layer that continues to
   settle under the weight of skier. Extended column tests continue to
   fail while isolating the back of the column. However, due to the
   shallow (16-20 inches) snowpack, there is no sliding layer, and the
   snowpack collapses on sagebrush and bitterbrush. In steep gullies and
   other wind loaded areas where the snowpack is deeper, there is a
   possibility a person could trigger an avalanche.

   Stability tests in the Bardinis and the Lakes Basin over the last two
   days show weakness at the depth hoar layer, though failures are in the
   upper end of easy with some in the moderate range. There is a layer
   about 12 to 15 inches down that is showing up in extended column
   tests, however, I am not getting propagation across the entire column.
   These results are an indication the snowpack is gaining strength but
   dont let your guard down- depth hoar can be a stability concern for a
   very long time.

   One final note: we tend to get complacent skiing the same area week
   after week and season after season. The up track in many places
   crosses slopes that are not safe. Many people stand directly in the
   run out zone at the bottom of this slope which is not safe either.

   BOTTOM LINE
   For today, the avalanche danger remains CONSIDERABLE in alpine
   wind-loaded terrain steeper than 35 degrees. The avalanche danger
   rating is MODERATE on all other slopes, however, isolated areas of
   CONSIDERABLE will be found in favored wind loaded gullies in places
   like the Sherwin Ridge, the Negatives and the Lakes Basin. Even though
   the snowpack is gaining some strength, the recent wind loading and the
   lurking depth hoar layer are good reasons to be cautious in steep
   terrain.

   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.