Eastern Sierra avalanche advisory

Updated December 25, 2009 - 10:55 am

The avalanche danger rating today is LOW. Generally safe avalanche conditions exist. Watch for unstable snow on convex terrain. Natural and human triggered avalanches are unlikely. Small avalanches may occur in isolated areas or extreme terrain.

Hazard Assessment

Clear dry weather is expected on Christmas Day. North winds have diminished to light northeast breezes until Saturday. While the Rockies report scary snowpack conditions and weak faceted snow failing under light loads, snowpack tests in the eastern Sierra reveal generally stable conditions. Look for isolated wind slabs from Tuesday's high north winds off ridgelines with convex rollovers. Otherwise, we are in the Sierra doldrums, waiting for more snow. Keep in mind that surface hoar has developed on many shaded slopes and in open areas above treeline and in open areas in the trees. If this layer is buried intact and preserved, we may find our favorite slopes plagued with a persistent weak layer. The shallow snowpack and continued dry weather could result in a general loss of strength in the snowpack, especially where the snowpack is less than 2 feet deep.

Christmas day will be a pleasant winter day with highs in the low to mid 30's at all elevations. Nights will continue to be cold in the teens with some higher elevations only dropping down to the mid 20's. Clouds in advance of a weak storm system could come in the afternoon. The weather forecast calls for a split jetstream to divert the majority of precipitation to Southern California. Only a few inches of snow are expected Sunday.