What might be California’s worst natural disaster in the future?

Earthquake, drought, or wildfire come to mind first. Every year, fire threatens to burn up acres of California. Right now, a scorching drought is drying up rivers and lakes across the West. The possibility of an earthquake remains in Californians’ thoughts especially since a “major” one hasn’t happened in some time. Not many people know that in the past, California suffered severe floods from prolonged rains during wet seasons. When I lived in California, the Sacramento Delta, formed by the confluence of the Sacramento and San Joaquin Rivers, and the Russian River north of San Francisco frequently flooded during winter storms. I distinctly recall one January when it rained every day. And California rains pour like a full-force bathroom shower almost all day.

The worst natural disaster for California that climate researchers are predicting is a megaflood, sometime this century, caused by a month-long series of rainstorms. One happened in 1862 and before that, in 1841. San Joaquin Valley became an inland sea and the upper Sacramento River flooded the land for miles, forcing Native Americans to abandon their villages and cutting off Captain John Sutter at Sutter’s Fort for months. Cattle, horses, elk, and deer were stranded on islands surrounded by the rushing water. So many sought refuge on tiny mounds of dry land that some animals were washed away and drowned. In 1815 a flood changed the Los Angeles River’s course. Again in 1825, the seasonal rains flooded the river through marshland and forests and cut a new channel, draining the land all the way to the ocean. A month of storms today might bring feet of rain, enough to flood hundreds of miles of California. A megaflood would displace millions of people, destroy cities and towns, and cost billions to repair. Experts say such a dramatic event is becoming more likely because of global warming.