A third day of rain, coastal flooding and gigantic waves along parts of the California coast forced residents to evacuate and left streets and parking lots flooded on Saturday, though forecasters predicted that conditions would soon improve in some areas.

On Saturday, warnings of coastal flooding and dangerous waves of up to 20 feet were in place for beaches and coasts in several California counties, including Los Angeles and Santa Barbara. The warnings were lifted on Sunday.

In coastal areas of Orange and San Diego Counties, a high surf warning was in place until 2 a.m. on Monday.

The National Weather Service said that dangerous coastal conditions would linger in the West Coast through Sunday, with “slow improvements expected into Monday.”

In Ventura County, an enormous rogue wave crashed ashore on Thursday, sweeping away cars, flooding houses and injuring eight people.

Fearing a similar incident, the authorities spent Friday bulldozing beach sand to create a mile-long berm in preparation for more high waves on Saturday.

The rogue wave flooded local streets in a neighborhood in the city of Ventura, causing damage to shoreline homes, the Ventura County Fire Department said on social media. Earth-moving trucks were being used to clear roads, according to a department spokesman, Andy VanSciver.

An evacuation warning was issued on Saturday for county residents in homes bordering the Pacific Coast Highway because of the risk of high waves damaging structures. The warning was lifted on Saturday afternoon.

Residents were told to avoid jetties and piers, where large waves could wash people away. The authorities also warned that significant beach erosion was possible.

Across the state, dozens of national parks and beaches were closed. All public beaches in the cities of Ventura and Oxnard, as well as some piers, will remain closed over the weekend.

The Weather Service in Los Angeles said that while the surf had subsided by Saturday afternoon, it warned surfers and beachgoers that “large, powerful waves, strong rip currents and longshore currents are still going — use caution!”

California State Parks also told outdoor enthusiasts to take precautions along the beaches.

In San Luis Obispo County, a street was flooded after high tides and high surf caused San Luis Creek to back up, the authorities said. In Los Angeles, photos on social media showed surf flooding a parking lot at Royal Palms Beach.

The rough conditions, which began on Thursday, were caused by storm systems that brewed over the Pacific Ocean.

Johnny Diaz contributed reporting.