Rain, coastal flooding and waves as tall as 25 feet were expected along parts of the West Coast through the weekend, after giant waves pummeled the California shoreline and prompted some evacuation warnings.
In Southern California, forecasters predicted waves of up to 25 feet and said that the threat of significant coastal flooding would last into Sunday night. For coastal areas in Orange County and San Diego County, high surf warnings were in effect through 2 a.m. on Monday. Coastal flood and high surf warnings were active for beaches in several counties, including Los Angeles, San Luis Obispo, Santa Barbara and Ventura through 10 p.m. on Sunday.
The Weather Service office in Los Angeles told surfers and beachgoers that the risk of drowning was high, and the California state parks system warned outdoor enthusiasts to be careful along the coast. More than a dozen state parks and beaches in California were fully or partly closed because of bad weather.
A high surf warning was in effect Friday night for more than six million people along the coasts of Oregon and California. The Weather Service office in Medford, Ore., said that it expected infrastructure damage and beach erosion from breaking waves up to 25 feet tall through early Saturday.
The large waves were part of a storm system that approached the West Coast early Friday. The Weather Service said in a forecast that moderate rainfall, becoming heavy in some places, was likely for much of California later in the day. A foot or two of snow was possible in the Sierra Nevada by Saturday night.
Some coastal areas of California, Oregon and Washington State were also under a gale warning until late Friday, meaning that wind gusts of 39 to 54 miles per hour were imminent or occurring.
There is evidence that the United States can expect more unusual and severe storms as the planet heats up, potentially striking in new places or at unexpected times of year.
Last winter brought some of the most ferocious weather that California had seen in decades, including many atmospheric rivers — narrow conveyor belts of water vapor in the sky — that dumped wave after wave of precipitation on already soaked ground.
The National Oceanic and Atmospheric Administration said in October that it expected conditions to be wetter than average across much of California this winter, partly because of the weather phenomenon El Niño.
John Yoon contributed reporting.