'Massive drought' is the primary weather concern in California

'Massive drought' is the primary weather concern in California

"Massive drought" may be the primary concern about the weather across the West right now amid the continuing threat of wildfires and earthquakes. But a new study warns of another looming crisis in California: "Megafloods."

Climate change increases the risk of future floods that could inundate multiple cities and displace millions of people across California, according to a new study released Friday.

She says a severe month-long storm can bring feet of rain — in some places, more than 100 inches — to hundreds of miles of California. Likewise, relentless storms had occurred in the past before the area became home to tens of millions of people.

The study says that each degree of global warming dramatically increases the possibilities and size of the next mega-flux.

"The storm sequence is larger in almost all respects," said Daniel Swain, a UCLA climate scientist and co-author of the study, in a future scenario in which the flood comes in hotter land. "There's more rain overall, more heavy rain every hour, and stronger winds."

Climate change is a factor in amplifying floods

The study found that climate change makes such catastrophic floods twice as likely to occur.

Swain said that such massive statewide floods had occurred every century or two in California over the past millennia, and the current risks of such events have been significantly underestimated.

Long before climate change, the California Great Flood of 1862 stretched 300 miles and 60 miles wide. According to the study, a similar flood will displace 5-10 million people, cut off major state highways for weeks or possibly months with massive economic impacts, and inundate major downtown valley cities and parts of Los Angeles.

The study expands on the 2010 "ArkStorm Scenario," named after the atmospheric rivers that would have fed the flood—a dimension of the Bible. "This is the first part of a plan to revisit this scenario, known as ArkStorm 2.0.

California's massive flood would be a trillion-dollar disaster

According to the University of California, Los Angeles, it is estimated that such a flood today would be a trillion-dollar disaster.

"Stockton, Fresno, and Los Angeles will be underwater even with the vast array of reservoirs, bulkheads, and sidewalks that exist today. It is estimated that it would be a trillion-dollar disaster, greater than any in world history," the statement read.

Swain said that Californians may have lost sight of severe flooding with droughts and wildfires getting so much attention. "There is the potential for destructive wildfires every year in California, but many years go by when there is no news of significant floods. People forget about it.

The researchers used new, high-resolution weather and current climate models to compare two extreme scenarios, according to the University of California, Los Angeles: one that will occur approximately once every century in the recent historical climate and the other in the projected environment of 2081-2100.

Both would involve a long series of atmospheric river-fed storms over a month.

What are atmospheric rivers?

Atmospheric rivers are ribbons of water vapor that stretch thousands of miles from the tropics to the western United States 250 to 375 miles wide, providing fuel for the torrential rains and snowstorms that can cause flooding along the West Coast.

While beneficial to water supplies, the National Oceanic and Atmospheric Administration said they could wreak havoc on travel, cause deadly mudslides, and cause catastrophic damage to life and property.