Good morning, this is Sue Burak with the Inyo National Forest Eastern Sierra Avalanche Center with an avalanche advisory for Wednesday, February 4, 2009. The Rock Creek Winter Lodge dinner and presentation is coming up this Saturday evening. Jan is making her delicious pizzas. Please RSVP to Jan, 935.4170. The moon is out and the snow will be fresh so come up for good food and learn about avalanches! MOUNTAIN WEATHER Enjoy one more day of well above average temperatures today before wet and windy weather moves into the area Thursday morning. Temperatures will drop around 15 degrees F tomorrow. 8,000 to 9,000 ft daytime temperatures will drop from the 50s to mid 30s. Higher elevations will be cool and windy with daytime highs in the mid 20s on Thursday. Night time lows at the 8,000 to 9,000 ft elevations will continue to be in the mid 20s until Saturday night, when the unsettled weather moves east and a clear colder night is expected. Southerly winds are expected today at all mountain areas with gusts to 45-50 mph. Southerly winds will increase Thursday with stronger gusts expected over the higher terrain. The much anticipated storm system is splitting with the southern portion of the storms energy impacting the western slopes of the southern Sierra, the Sierra crest and the Mammoth area. The best estimate for snowfall is for 6-10 inches above 9,000 ft on Mammoth Mountain and the immediate surrounding mountains by Thursday night. Snowfall amounts are expected from another storm due to affect the east side Friday afternoon. Though it is not known how far south the main energy of this storm will come, the atmosphere will already have abundant moisture in place. With little jet stream support, snowfall will result mostly from orographic lifting as the storm tracks from the Central Valley. Another foot of snow could fall on Mammoth Mountain and the Mammoth Lakes Basin by Saturday morning. June Mountain is expected to receive about 1 to 1.5 ft of new snow and could receive additional snowfall from upslope showers Saturday and Sunday. Snowfall east of the Sierra Crest will drop off quickly with only a couple of inches of snow expected in the Lee Vining and Crowley Lake areas. SNOWPACK AND AVALANCHE DISCUSSION Snow surfaces on open slopes in high elevation, north facing terrain are variable, ranging from thin to thick wind crusts and breakable crusts to loose recrystallized snow and surface hoar in sheltered shallow gullies. Total snowpack depths range from 16 to 4 feet on east and north facing slopes at the 11,000 to 12,000 ft elevation in Rock Creek. The four feet snowpack depths are mostly found in isolated gullies. There is more snow in the Mammoth Lakes Basin with 1.5 ft to 5 feet above 8,500 feet. Snowpit results and observer reports show the hard layer or lens that separates the December/January snow from the recent storm snow has small facets developing above and below the layer. However, the snowpack does not react at this layer during stability tests. New snowfall will add a new load to this layer and will need to be evaluated during and after the storms. A dry January has allowed our snowpack to stabilize in most locations, and avalanche conditions are generally safe on most slopes. There are a few reports of very small wet point release slides on steep southeast aspects in the June Mountain area, and clear skies today will likely result in similar solar radiation effects on southern aspects. With snowfall and wind in the forecast for Thursday through Saturday, the dry, recrystallized snow found in open terrain above treeline could be a weak layer for new storm snow. Thin wind crusts are another suspicious layer in the higher terrain. With gusty winds from the south forecasted for tomorrow, wind slabs will become the most immediate avalanche issue. The main avalanche potential will be in north facing terrain. For today, the avalanche danger rating remains LOW. The outlook is for increasing avalanche danger as the forecasted storm moves into our area. The LOW avalanche danger rating means snow conditions are generally safe, though watch for unstable snow on isolated terrain features. BOTTOM LINE For today, the avalanche danger rating remains LOW. The outlook is for increasing avalanche danger as the forecasted storm moves into our area. The LOW avalanche danger rating means snow conditions are generally safe, though watch for unstable snow on isolated terrain features. The outlook is for increasing avalanche danger as the forecasted storm moves into our area. 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.