Good evening, this is Sue Burak with the Eastern Sierra Avalanche Center with an avalanche advisory posted for January 7, 2008. MOUNTAIN WEATHER Snowfall is ending over the Mammoth and June Lake areas. Scattered snow showers will remain over the higher elevations for the next two days. Highs at 9,000 ft will be in the low to mid 20s today, warming to 30 on Tuesday. Night time lows will be around 10 F. Winds will continue to be from the southwest today and increase tonight. Ridgetop winds are expected to reach 70 mph tonight through Tuesday, then the dreaded north winds will come Wednesday. -p- For Bishop Creek, there will be a few scattered snow showers today through Tuesday. Daytime highs today will be in the low 20s, warming a few degrees on Wednesday. SNOWPACK AND AVALANCHE DISCUSSION There are two main avalanche concerns today and for the next few days. -p- Before the storm, slopes with a shallow snowpack had and continue to have a faceted or depth hoar layer at the base of the snowpack. If a slope did not avalanche during the storm, there is another 3-4 feet of new and wind loaded new snow applying a force to these weak grains. Today, loud slope settlement and shooting cracks stopped our uphill progress on a north facing slope of 28 degrees. An extended column test failed while the column was being isolated. Depth hoar and faceted grains do gain strength over time but how long this will take requires digging, looking at the snow crystals and doing stability tests, especially the extended column test. -p- There are two huge climax avalanches on McGee Mountain. The Trailer Park gully and McCoys went Saturday night. The starting zones are stripped almost to the ground and dirt and trees can be seen in the debris that came quite close to Crowley Lake Drive. -p- Other reports of whumpfing came from June Lake where a group of experienced local skiers ventured off piste. Rock Creek Lodge reported settlement on the flats around the Lodge. They skied the east facing slope across from the Lodge and did not experience any slope settlement. -p- In the Mammoth Lakes Basin, the snowpack is deeper and new snow fell on firm wind packed snow. Based on snowpits done immediately before the storm, basal depth hoar was found only on shallow, wind stripped south aspects. On north and east aspects, small faceted grains were gaining strength. The main concern is wind loading from the relentless southwest and west winds over the last 3 days. Use caution, ski cuts and cornice drops if possible to test the slope before you drop in. -p- -p- -p- Storm discussion -p- Snowfall totals from Friday through Sunday morning range from 40-50 inches from Mammoth north to Leavitt Lake. Rock Creek and the southern Sierra picked up 30-40 inches of new snow. As all of us who have been shoveling snow, the Friday storm was wet with densities ranging from 13-18% along the Crest. The water content at Mammoth Pass went from 8 inches to 16 inches in three days. Bishop Pass went from 23 to 56 inches including settlement. Leavitt Lake went from 36 to 96 and picked up 11 inches of water. The southern Sierra received over 40 inches of snow and 7-8 inches of water. -p- As far as this storm being a drought buster, the California Data Exchange Center reports close to average snow water contents for this time of year. More snow is needed to stay close to average for January. However, a few days of dry weather will be nice. -p- BOTTOM LINE For Monday, the avalanche danger continues to be HIGH for all areas that had a shallow snowpack before the weekend storms. This includes the Tele Bowls, the area around Mt. Morrison, McGee Mountain, Little Round Valley and Rock Creek. Natural and human triggered avalanches are likely on a variety of aspects and slope angles due to weak snow at the bottom of the snowpack. Whumpfing and shooting cracks have been observed. Any slope that has not avalanched is suspect. I do not have any information from the Mammoth Lakes Basin. Based on the amount of new snowfall and strong winds over the last three days, there is considerable to high avalanche danger on steep wind loaded slopes. Watch out for unstable wind drifts and soft slabs in steep convex terrain. Large areas of unstable snow still exist on north and east aspects. A skier or rider could probably trigger a soft slab avalanche today. I will post avalanche information on the Bishop Creek area in the next couple of days. 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.