The California Water Resources website has a lot of snow survey information:
http://cdec.water.ca.gov/snow/current/snow/First, the "Snow Course" menu will help you find the location of interest. Each area has a three-digit code, which is used for searches. The Snow Courses are areas of major water shed interest (drainages). The snow sensors and physical surveys are usually in meadows, not on mountain summits like Whitney.
