Good morning, this is Sue Burak with the Eastern Sierra Avalanche Center. Today is January 31, 2008. MOUNTAIN WEATHER More unsettled weather is on tap through the weekend. With cloudy skies today, temperatures will remain cool with daytime highs at the 8,000 to 9,000 elevations in the mid to upper 20s with lows around 15 F. Higher elevations could receive 2 to 5 of snow from Mammoth northward. The Reno NWS has issued a high wind advisory for 10 AM through 10 PM Thursday night. Winds will increase ahead of a strong cold front. Expect south to southwest winds 15-30 mph with gusts to 50 mph. The 395 corridor could see wind gusts to 60 mph. Once again, elevations above 9,000 ft could see gusts from 90 TO 115 mph. The NWS Las Vegas office has issued a high wind watch for the Owens Valley and the eastern slopes of the Sierra south of Mono County. This watch goes into effect Thursday evening into Friday morning above 5,000 ft. and the Owens Valley could see 60 mph west winds tonight. After this storm moves east, there is one more storm for Saturday night into Sunday morning. This will be a warmer storm with a potential for significant snowfall in the mountains. The latest model runs are showing this system will move slower and dig deeper than previously expected. The position of the trough off the Oregon/ Washington coast will help to draw tropical moisture and could be a major precipitation event for Mono County. By Monday, a high pressure ridge moves in for warmer temperatures and sunny skies for most of the week. SNOWPACK AND AVALANCHE DISCUSSION We have had 2 major wind events, one major snowfall event and 2 large avalanche cycles since Saturday night. The 4-5 of snowfall yesterday was blown around in an epic southwest and west wind event. Medium to large avalanches were observed from last nights event off the Mammoth Crest, San Joaquin Ridge and McGee Mountain. Avalanches occurred mainly on northern and east facing slopes. Winds were so strong that road cuts above 395 north of Long Valley avalanched. Cornices grew and the wind pillows that have not avalanched yet grew thicker. Fracture depths were variable and stability tests were inconsistent today- no real culprit layer exists due to the multiple wind layers. I did not see any soft slabs today, only hard wind slabs created by extreme wind speeds. The good news is that hard slabs are more difficult to trigger than soft slabs, but the bad news is that they tend to propagate farther and make a much larger and more deadly avalanche. Also, the stiffer the slab, the farther above you the fracture line will usually form, and the harder it will be to escape. The reason for this is that stiff slabs tend to spread a person's weight over a larger area. West facing slopes and ridges are stripped of all snow. Most of the loading occurred on north to east aspects. Watch out for pillows today- hard slabs vary in thickness. You may be lulled into complacency skiing across a thick hard slab but as soon as you get to the edge of the slab near a ridgeline, it gets thinner. These are the text book locations for triggering a large slide. BOTTOM LINE Windloading continues to be the main avalanche concern as storms continue to move through our area. For today, because human triggered slides are still probable, the avalanche danger is CONSIDERABLE on all wind loaded terrain as well as any slope steeper than 35 degrees. All other slopes will have a MODERATE avalanche danger. Avoid alpine terrain and enjoy skiing in nice powder in the trees. 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.