Likelihood of megaflood in California has doubled due to climate change, UCLA scientist says

Rob McMillan Image
Tuesday, August 16, 2022
EMBED <>More Videos

In an interview with ABC7, a climate scientist with UCLA discussed the likelihood of a devastating megaflood in California -- and the possibility of reallocating floodwaters to help combat a drought.

LOS ANGELES (KABC) -- Catastrophic wildfires are a fact of life in California -- and disastrous flooding could be next.

According to a newly released study, climate change has already doubled the likelihood of a so-called megaflood.

Such a disaster could be marked by heavy rainfall every day for an entire month.

"There are individual, very long storms that are part of these scenarios," Daniel Swain, a climate scientist with UCLA and co-author of the study, said in in interview with ABC7. "But we're mainly assessing the propensity for three-to-four week-long sequences that produce cumulatively very high precipitation."

According to Swain, it's not a matter of if but when a megaflood will occur. In fact, it's happened before in California -- including in 1892.

On average, a megaflood takes place five-to-seven times every thousand years. But because of climate change, the risk of one happening has doubled.

So, what would a megaflood look like?

Megaflood coming to California, experts warn, may cause $1 trillion in damage

"Think the highest king tides you've ever seen," Swain said, "and then add a foot or two on top of that, and add an additional flooding risk coming from all the water rushing down from the hills from the rainfall."

But the news isn't all bad, according to Swain -- if infrastructure can be built to harness the water that a megaflood would bring.

"If we can reallocate these floodwaters to percolate back into the aquifers," he said, "then it both reduces the flood risk to urban areas in the moment of the flood and also then increases our resilience to the inevitable drought that would follow."