Rain, coastal flooding and waves as tall as 30 feet were expected along parts of the West Coast on Friday, a day after giant waves pummeled the California shoreline and prompted some evacuation warnings.

More than six million people in coastal areas of California and Oregon were under high surf warnings overnight as breaking waves posed an “especially heightened threat to life and property,” according to the National Weather Service.

“Dangerously large” waves about 28 to 33 feet tall, and potentially up to 40 feet tall, were forecast overnight in some coastal spots in the San Francisco Bay Area and for some parts of Central California, where a few communities in Santa Cruz County had received evacuation warnings a day earlier.

A high surf warning for the Bay Area and the Central Coast expired at 3 a.m. local time. But a high surf advisory, indicating a lower level of risk, along with a coastal flood advisory, were scheduled to last for several more hours.

Separately, a high surf warning was set to remain in effect through Saturday for more than four 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 30 feet tall.