Once you get past Yosemite, pretty much all of the reservoirs are empty to less than half full. Majority of the streams are gone.
It gets worse the further you head south. Kings and Sequoia are pretty much decimated forests from the fires and beetles. Dead trees for as far as you can see. Given the lack of water, I expect them to be desert in just a few more years.
There are quite a few hydro power generation stations deep in the mountains that I had no idea existed. I suspect they will close down as well. I wonder what effect that will have on California power supply over the coming years. That said, it was pretty clear that PG&E is working on updating the infrastructure as they are all over the place working on things.
If I hadn't seen it for myself, I wouldn't believe it. The extent of damage is pretty massive and it would take quite a lot of rain to 'fix' things. So much so that it would probably end up just flooding everything, creating just as much of a mess.