Good morning, this is Sue Burak with the Eastern Sierra Avalanche Center with an avalanche advisory posted on Thursday, April 24, 2008. MOUNTAIN WEATHER The cold front that brought high winds and cold temperatures the last few days is moving east to the Great Basin and Idaho. This mornings temperatures are reminiscent of January with lows in the teens and single digits. Winds decreased during the night with light winds recorded on the top of Mammoth Mountain this morning. As a flat high pressure ridge builds into California, temperatures will begin a slow warming trend today as the trough moves east and a high pressure ridge moves onto the west coast. After yesterdays wind and cold temperatures reaching the low 30s, today could see daytime temperatures in the upper 30s to 40F today at 9,000 ft. Winds will be from the northwest today with increasing winds on Friday. The weekend looks pleasant with light winds and temperatures in the 40s at the higher elevations. The 5 to 7 day forecasts calls for another trough to affect our weather by Tuesday. A cooling trend will begin on Monday and light precipitation by Wednesday. As one of the Reno forecasters stated last night, All we can do is sit back and enjoy the spring ride. SNOWPACK AND AVALANCHE DISCUSSION Isolated snow shower activity resulted in varying snowfall amounts. Snowfall amounts measured from snow pillow installations show range from 5 inches at Leavitt Lake, 3 inches on Tioga Pass, 4 inches at Slide Canyon and a couple of inches on Mammoth Mountain. Given the strong gusty winds yesterday, I am sure these are conservative estimates, with the possibility of wind drifted snow on northern aspects approaching 6 to 8 inches. South of Mammoth, very little snow fell. Unfortunately, not enough snow fell to fill in the valleys between the fins and sun cups that are populating many areas of lower angle terrain. Most of us are experiencing traveling over acres of sun cups and early stage neve penitentes on lower angle east through west aspects above 10,000 ft. A couple of ski patrollers from the Canyons Resort in Utah reported high winds and acres of frozen deep sun cups on the Palisade Glacier last weekend. Plans to ski the U Notch and the V Notch were abandoned due to the blue ice in the gullies. A party traveling over Mather Pass reported an ice lens about 12 inches down from the surface. The same ice lens has been found in the Witcher Bowl and the east facing gullies on Mt. Morgan north. Snowpack structure remains a concern over the next four days as both daytime high and night time lows increase. Strong solar radiation can rapidly thaw surface crusts which occur as early as 10 AM by the weekend. For today, the avalanche danger rating is LOW with isolated areas of MODERATE in steep north facing terrain with recent deposits of wind drifted new snow. These conditions will be found in the Mammoth area north to the Tioga Pass area. BOTTOM LINE For today, the avalanche danger rating is LOW with isolated areas of MODERATE in steep north facing terrain with recent deposits of wind drifted new snow. These conditions will be found in the Mammoth area north to the Tioga Pass 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.