The links that clydescope provided are great resources however the snow pack of the Mammoth Pass area should not be used as anything but a guide for what may be transpiring in the Southern Sierra.
The CA Dept of Water Resources (
http://wwwdwr.water.ca.gov/) maintains a load of data although I suspect that it is not very usable (like that which MM Patrol maintains).
The January 1 report suggested that the Southern Sierra was above normal snow pack; Central (Mammoth Lakes area) and Northern Sierra (Lake Tahoe area) below normal, however the most recent storminess has (I believe) benefited the Northern and Central portions of the range more than the Southern section.
I believe that the next official report is delivered on or about April 1.