And, reports CBS News Correspondent John Blackstone, a has sent a clear warning: Disaster may come with the next heavy rain.
Gov. Arnold Schwarzenegger has declared a state of emergency in seven northern and central California counties, providing more than $1 million for urgent levee repairs.
"This is," he says, "a reminder that our levees are extremely vulnerable."
From the air, Stein Buer of the examines known weak spots in the levees that protect much of his city.
He describes Sacramento as "the most vulnerable of the top 30 largest cities in the United States."
Originally, Blackstone points out, the levees north of Sacramento were meant to protect farmland, but the area has become a sprawl of suburbs, with new subdivisions built on low-lying land right to the edge of the levee.
California's booming real estate market is now gaining a new appreciation of the dangers of life on low ground, Blackstone notes.
Says University of California, Berkeley environmental engineer Robert Bea, "This time, if we let the levees go in the metropolitan area of Sacramento, we've flooded the city, and that's serious. … This is very much like New Orleans. We could essentially destroy the homes for perhaps a half a million people."
New Orleans, says Blackstone, has provided the best argument yet for fixing California's levees.
"We would rather invest a little money now than pay 10 to 100 times that amount in the future," Bea observes.
But, Blackstone concludes, fixing California's levees is shaping up as a race against the weather.