The planet’s rising temperatures mean California is at greater risk of a “superstorm” that could flood the state’s Central Valley, causing damage that would dwarf even a major earthquake, scientists have warned.
At a conference in Sacramento last week, 117 researchers brought together to study flooding risks in California presented a chilling model they say could become a distinct possibility: A winter storm that brings warm South Pacific air over parts of California, creating an “atmospheric river” that could bring 10 feet of rain over 40 days, flooding large tracts of the state and bringing flood water to nearly a quarter of the state’s homes.
Such a storm could bring water into California at a rate equivalent to that of 50 Mississippi rivers, the climate model projected.
As sensational as that scenario sounds, researchers say it’s based in historical reality: Such storms have hit California before, most notably in 1861 and 1862, when floods turned a 300-mile stretch of the Central Valley into a lake. The New York Times reports:
The storms lasted 45 days, creating lakes in parts of the Mojave Desert and, according to a survey account, “turning the Sacramento Valley into an inland sea, forcing the state capital to be moved from Sacramento to San Francisco for a time, and requiring Gov. Leland Stanford to take a rowboat to his inauguration.”
“We think this event happens once every 100 or 200 years or so, which puts it in the same category as our big San Andreas earthquakes,” said Lucy Jones, chief scientist of the US Geological Survey Multi-Hazards Demonstration Project, which created the model with the help of researchers from FEMA and the California Emergency Management Agency (Cal EMA).
According to the scientists’ model, the Los Angeles, San Francisco Bay Area and San Diego regions would also be affected by flooding. Damage to property could top $400 billion, while lost business revenue could cost the state another $325 billion.
That is “nearly three times the loss deemed to be realistic … for a severe southern California earthquake, an event with roughly the same annual occurrence probability,” the researchers reported.
The researchers’ dire warning comes as massive flooding hit three separate parts of the world in the past week: Australia, where large tracts of Queensland state have been inundated; Sri Lanka, where at least 40 have died and one million have been displaced; and Brazil, where the death toll from flooding has exceeded 600.
The New York Times states that the likelihood of such a “superstorm” increases as climate change takes hold. “Climate scientists have for years noted that the rising temperature of the earth’s atmosphere increases the amount of energy it stores, making more violent and extreme weather events more likely,” the paper reports.
The researchers have dubbed their model “ARkStorm,” short for “atmospheric river 1,000.”
“An ARkStorm raises serious questions about the ability of existing federal, state, and local disaster planning to handle a disaster of this magnitude,” the researchers report. “A core policy issue raised is whether to pay now to mitigate, or pay a lot more later for recovery.”