Megaflood Could Decimate Parts of California, New Study Claims

Move over, earthquakes. Scientists say California is at risk of a megaflood that would do far more damage than any quake and could prove to be the most costly geophysical disaster to date.

The study was conducted by researchers from the University of California Los Angeles (UCLA) and the National Center for Atmospheric Research. It is based on high-resolution weather modeling and existing climate models.

The researchers found that climate change has already doubled the likelihood of an extreme storm in California and, with each additional degree of global warming, the chances of a “megastorm” this century grow. The study projects that end-of-the-century storms will generate 200% to 400% more runoff in the Sierra Nevada Mountains and more precipitation falling as rain instead of snow.

According to the report, California’s Central Valley, including Sacramento, Fresno and Bakersfield, would be among the hardest hit. Some communities could see eight feet of water, with stop signs completely submerged and freeways closed for weeks. 

“Stockton, Fresno and Los Angeles would be under water even with today’s extensive collection of reservoirs, levees and bypasses,” according to a press release. “It is estimated that it would be a $1 trillion disaster, larger than any in world history.”

With so much focus on the drought, earthquakes, and wildfires, many Californians don’t realize just how vulnerable the Golden State is to flooding. The Great L.A. Flood of 1861 and 1862 was large enough to change the physical makeup of Los Angeles and Orange Counties forever. You can read more about it here.

“In the future scenario, the storm sequence is bigger in almost every respect,” said Daniel Swain, UCLA climate scientist and co-author of the latest study. “There’s more rain overall, more intense rainfall on an hourly basis and stronger wind.”