Good morning, this is Sue Burak with the Eastern Sierra Avalanche Center with a weather and snowpack discussion for January 2, 2008. MOUNTAIN WEATHER The beautiful warm and windless weather is about to change in a big way. After reaching highs in the upper 40s today, today will be 5-10 F cooler with breezy conditions at the 8,000 to 9,000 ft elevations. Winds are increasing from key high elevation sensor locations. After a calm day yesterday at the top of Mammoth Mountain and the 12,300 ft elevation on Mt. Warren, winds from the south and southwest picked up last night as the high pressure ridge moves east. Temperatures topped out today with Tioga Pass and Main Lodge reaching the mid 40s. Dana Meadows saw a high of 48 F and the 9,400 elevation on Mammoth Pass reached 52 F!!. The high on the chilly, 11,000 ft Tyndall Plateau reached 39 F. Lower elevations saw a cooling today with Toms Place reaching 51 after a high of 54 on Monday. Bishops high today was 50F, 10 degrees cooler than the Dec 31 high temperature of 60 F. The low this morningin Bishop was 13 F compared to the low 20s at Main Lodge. Increasing winds will mix out the inversion today. A winter storm watch has been posted by the Reno and Las Vegas NWS forecast offices for Mono County and the east slopes of the southern Sierra and the White Mountains. Light snowfall will begin Thursday afternoon and continue through Friday morning. This storm is weak and only a few inches are expected but dont worry, the main event begins Friday afternoon. Very heavy snowfall is expected Friday night into Saturday mid day with several feet expected by Saturday afternoon. Strong winds up to 50 mph will create whiteout and blizzard conditions along the 395 corridor, so please dont expect to travel to or from Reno on Friday night. Mammoth Mountain and the Sierra Crest will experience 100+ mph winds. Las Vegas NWS expects 2-4 feet of snow above 6,000 ft from Friday into Saturday morning from Bishop creek south. High winds over 70 mph will combine with blowing and drifting snow to produce whiteout or blizzard conditions. Snowfall will briefly taper off Saturday morning before another storm brings more heavy snow and high winds to the area late Saturday through Sunday. Snow levels will initially be around 8,000 ft but lower to the Owens Valley by Sunday morning. SNOWPACK AND AVALANCHE DISCUSSION Since Friday of last week, daytime temperatures have slowly been increasing with the finale occurring on New Years Day with temperatures in the 40s above 9,000 ft. The gradual warming along with light winds have worked wonders on snowpack stability though skiing conditions have deteriorated in some places with thin crusts forming on west and some east aspects. Surface hoar has returned with clear, cold nights. With winds increasing tomorrow and clouds moving into the area, conditions are not favorable for surface hoar formation but I would not take anything for granted right now and will be on the lookout for the glitters the next two days. Snow stability tests show the basal depth hoar and faceted layers have gained some strength the last few days. Hard wind slabs in the alpine zones will most likely be the initial sliding surface for the upcoming storm snow. Observer reports from Old Mans Bowl, the upper reaches of Virginia Lakes and the favored ski slopes in the Mammoth Lakes Basin all report hardpack conditions. In some gullies, I have found nice wind blown snow over hard pack. It is difficult to get results in compression and extended column tests. If 3-5 inches of snowfall an hour occur Friday afternoon into Saturday, the sudden load on the snowpack is sure to create dangerous avalanche conditions. Very strong winds will add loading to the already loaded slopes. Most avalanche occur during and immediately after a storm, so avoid the temptation to go for pow right after the storm. Up high above tree line, there may be no pow, only dangerous soft slabs waiting for a trigger. The avalanche danger rating for today is LOW with isolated areas of MODERATE danger in steep wind loaded terrain in alpine zones. This danger rating expires in 24 hours. During the storms, I will be updating on a daily schedule. BOTTOM LINE The avalanche danger rating for today is LOW with isolated areas of MODERATE danger in steep wind loaded terrain in alpine zones. This danger rating expires in 24 hours. 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.