The California Department of Water Resources regularly measures the snow depth in a number of strategic places, and I believe most of that data is online. The raw data isn't going to be that much good to you, but if you see percentage numbers compared to a normal year, that can give you a good idea of what you'll be into. For example, if I see that an area is at 120% of normal snowpack, then I will delay my summer trip there by 2-3 weeks.
This year, for one particular area, I delayed my trip by one week compared to normal. For another area, about two weeks.