Spots 
California faces $2-3 billion flood threat as El Nino strengthens in the Pacific Ocean El Nino triggers atmospheric rivers and Kelvin waves boosting sea levels and flood risks Early storms caused severe beach erosion, damaging homes and infrastructure in Southern California California is facing a potentially multi-billion-dollar flood threat as El Nino gathers strength in the Pacific Ocean.
The warming El Nino phenomenon tends to unleash powerful storms in the Pacific, including atmospheric rivers, some of which are named the "Pineapple Express" if they originate near Hawaii.
The heaviest rains tend to come during the winter months. But El Nino is already creating chaos on some California beaches, with flood risks expected to rise in the weeks ahead.
Disaster modelers at Climate X, a risk analytics firm backed by Google Ventures, estimate that El Nino could cause $2 billion to $3 billion in losses from flooding and mudslides statewide through the winter, based on damage inflicted during past events.
On average, California tends to see about $500 million a year in flood damages, according to estimates from the nonprofit Climate Central.
An emerging threat comes from a pulse of Kelvin waves that boost sea levels through the Pacific Ocean, said Michael McPhaden, a senior scientist affiliated with the University of Washington's Cooperative Institute for Climate, Ocean and Ecosystem Studies. The massive, underwater waves - which result from changing winds during El Nino - can intensify coastal flooding when extreme storms and high winds pound California's shoreline.
The next significant wave is expected to land in California by early October, according to McPhaden. So far, Kelvin waves have boosted sea levels up to 16 inches (40 centimeters) on their trek through the Pacific, said Paul Roundy, an El Nino researcher and atmospheric science professor at the University at Albany.
They won't be the first coastal threat California has faced since El Nino developed in June. For weeks, the phenomenon has been supercharging hurricanes and typhoons through the Pacific, flinging tropical winds and heavy surf toward the US West Coast.
In early September, remnants of storm Marie slammed the Southern California coastline and all but erased some beaches and seawalls. More than a dozen oceanfront homes were severely damaged in Orange County, with at least one marked for demolition.
These early bursts of "substantial" beach erosion months ahead of El Nino's peak "raise the potential for more severe coastal flooding, erosion, and infrastructure damage," said Adam Smith, a Climate Central disaster researcher.
California faces $2-3 billion flood threat as El Nino strengthens in the Pacific Ocean El Nino triggers atmospheric rivers and Kelvin waves boosting sea levels and flood risks Early storms caused…