Good morning, this is Sue Burak with the Inyo National Forest with an
   avalanche advisory posted for Thursday January 8, 2009.

   MOUNTAIN WEATHER

   Daytime high temperatures jumped 10 F today with higher elevations like
   Tioga Pass, Dana Meadows and Mammoth Pass reaching highs near or
   greater than 50F. Temperatures stayed warm overnight with many low- and
   mid-elevation stations recording highs above freezing. Wind speeds also
   spiked last night, with wind speeds averaging in the 40s and gusting to
   60 + mph on Mt. Warren, Mammoth Mountain and Lake Sabrina. Snow sensor
   site are recording an inch or two of settlement due to the warm
   temperatures

   For Thursday, skies will be partly cloudy and cool with a chance of
   snow showers in the afternoon. Morning highs will be in the upper 40s
   but temperatures will fall Thursday afternoon with cold front passage.
   Highs above 10,000 ft will be in the 20s. Southwest and west winds will
   pick up and gust up to 60 mph.

   Fridays weather will be dominated by high pressure building into the
   area. Skies will be clear, temperatures will warm and expect this to
   continue into next week.

   Atmospheric and oceanic conditions reflect La Nina. Recently, negative
   equatorial SST anomalies have strengthened across portions of the
   central and eastern Pacific Ocean. Based on recent trends in the
   observations and model forecasts, La Nina conditions are likely through
   early 2009. However, a change in this dry pattern is expected by some
   at the Reno office. The change will occur around January 17 and could
   be a week of wet stormy weather.

   SNOWPACK AND AVALANCHE DISCUSSION

   The warm temperatures and wind have created what one might generously
   call variable snow surface conditions wind pack, damp powder, and
   crusts. You can sniff out cold dry snow on sheltered, mid- to
   upper-elevation slopes away from exposed ridgelines, but you might pay
   a price to get there and back.

   The primary avalanche concern is the deeply buried persistent weak
   layer of facets at the base of the snowpack. In some areas I traveled
   today, the depth hoar layer still has a well defined rain layer or two
   in the mix of rotten snow on the ground. The layer has been responsible
   for many reports of whumpfing, but there have been no recent reports
   and I did not hear any whumpfing today. The most critical areas for
   triggering avalanche associated with this weak layer are slopes covered
   with small trees, boulders and bushes, possibly buried just below the
   surface, that act as both trigger points and stress concentrators for a
   propagating slab.

   A secondary avalanche concern is wind drift and slab formation with the
   gusty west winds for Thursday afternoon. However, clear skies prevail
   on Friday so watch out for thin wind slabs that may form tomorrow
   afternoon.

   BOTTOM LINE

   In the Mammoth to June backcountry, the avalanche danger is estimated
   to be LOW. On steep, upper elevation shady slopes the avalanche danger
   remains MODERATE. In these locations, a layer of facets buried 3 feet
   deep or more is still capable of producing an avalanche. On shady
   aspects, it will be wise to avoid slopes greater than 35 degrees
   especially those with rocky and/or shallow features where a slide could
   more easily be triggered.

   In the lower elevations of the Mammoth Lakes Basin, the avalanche
   danger today is estimated to be LOW. There is weak, faceted snow at the
   base of the snowpack on many of these slopes, but the layer has had
   more time to strengthen.

   With overnight lows in the valleys above freezing, it may also be
   possible to trigger wet loose slides on steep, southeast facing slopes,
   especially in the upper Yost and approaches to San Joaquin Mountain.

   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.