If it's big and hairy, then the description you gave is mostly likely for a California Trapdoor Spider. If it's not so big, and it seems to be extremely agile, then it is likely a type of jumping spider. If that were the case, it would be about the size of nickel. If it's almost tarantula size, it's probably the trapdoor spider. There are not really any other specimens in the region that match the aforementioned color pattern.
