Megadrought may be the main weather concern across the West right now amid the constant threat of wildfires and earthquakes. But a new study warns another crisis is looming in California: “Megafloods.”
Climate change is increasing the risk of floods that could submerge cities and displace millions of people across the state, according to a study released Friday.
It says that an extreme monthlong storm could bring feet of rain – in some places, more than 100 inches – to hundreds of miles of California. Similarly unrelenting storms have happened in the past, before the region became home to tens of millions of people.
Now, each degree of global warming is dramatically increasing the odds and size of the next megaflood, the study says.
When floods hit in a warmer planet, “the storm sequence is bigger in almost every respect,” said Daniel Swain, UCLA climate scientist and co-author of the study, in a news release. “There’s more rain overall, more intense rainfall on an hourly basis and stronger wind.”
Climate change a factor in megafloods
In fact, the study found that climate change makes such catastrophic flooding twice as likely to occur.
Swain said that such massive statewide floods have occurred every century or two in California over the past millennia, and today’s risk of such events has been substantially underestimated.
Long before climate change, California’s Great Flood of 1862 stretched up to 300 miles long and 60 miles across. According to the study, a similar flood now would displace 5 million to 10 million people, cut off the state’s major freeways for perhaps weeks or months with massive economic damage, and submerge major Central Valley cities as well as parts of Los Angeles.
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