Residents of The Golden State have been living with the knowledge that a big earthquake could strike at any time.
To help prepare or such an event, federal and state emergency planners have been studying what a really big quake would do to their ability to respond.
The two-year study has painted a frightening scenario.
Ducking and covering will no longer be enough to deal with a 7.8 magnitude earthquake rumbling in California.
A two-year study of past quakes suggests some 1,600 fires could break out and severely tax firefighters' ability to reach and successfully deal with them all.
What the recent Baja quake did to California's Imperial Valley, some 35 miles away, has shown that quake victims might have to look to other states, not just neighboring counties, for vital help.
"And in Imperial we had water clarifiers for the water district that were knocked out," Steven Sellers, with the California Emergency Management Agency, said. "We had to bring in temporary water clarifiers, which are on semi-trailers, from New York."
However, so many roads might be blocked or severely damaged and unusable that water couldn't reach the neediest areas.
"The roads being down, the rails being down, the airports being closed," Justin Dombrowski, also with FEMA, said. "It's harder to get to the people who need our help."
"The real shocker to me was the impact on infrastructure," Sellers said. "What I mean is, like, your water system. We're talking not a couple of hours a day, we're talking some places days, maybe weeks, before we can get those systems back in place."