SANTA CRUZ — Mudslides buried portions of southbound Highway 17 and Soquel San Jose Road on Wednesday in an atmospheric river expected to whip the Central Coast with 50 mph gusts through Thursday, according to the National Weather Service and county road officials.

Wind knocked large trees across Ice Cream Grade, which was among eight county roads blocked or reduced to a lane as more than 4 inches of rain fell in Ben Lomond and roughly half that amount drenched the county’s low elevations Wednesday, according to Sentinel weather watchers.

Residents of Paradise Park reported excess runoff below the 17-acre Rincon Fire burn scar in the back of the neighborhood. Community leaders advised those residents that flooding was possible into Thursday with the social hall prepared to open for anyone displaced.

Flooding was a concern along upper San Lorenzo River, which was expected to reach minor flood stage by Thursday afternoon, said Scott Rowe, a National Weather Service meteorologist at the Monterey office.

“For the San Lorenzo, flood stage is 16.5 feet at Big Trees. It’s forecast to reach 16.6 feet,” Rowe said. In Santa Cruz, the river rose to 14.5 feet — about 6 feet below flood levels — Wednesday.

The Pajaro River is not expected to surpass its flood stage, Rowe said. Monterey County sustained extensive wind damage while most flood reports originated in Santa Cruz County, he said.

Flood advisories were issued throughout the Central Coast through 10 a.m. Thursday. Advisories are issued when flooding might cause “significant inconvenience” without the severity required of a flood warning, according to the National Weather Service.

In Santa Cruz on Wednesday, a Brookwood Drive motorist escaped a flooded area that left a vehicle parked with water above the vehicle’s hood.

By Wednesday afternoon rush hour, multiple wrecks amassed across the county with a four-vehicle pile-up on southbound Highway 17 near Pasatiempo, authorities said. That happened after the southbound left lane was opened with loose earth still blocking the right lane.

Eight county roads were closed or reduced to one lane with three flooded and others blocked by landslides and fallen power lines, according to Santa Cruz County Public Works. Aptos Beach Drive, Buena Vista Drive and Paulsen Road flooded and were closed. The threat of inundation forced county officials to close Murphy Crossing between Highway 129 and San Juan Road.

Soquel San Jose Road was closed at mile marker No. 9 Wednesday amid fallen power lines.

There were 84 residents without electricity in Santa Cruz County on Wednesday afternoon, PG&E spokeswoman Mayra Tostado reported. More than 10,000 Central Coast customers had no electricity Wednesday afternoon.

And it isn’t over.

The system is expected to slam the entire West Coast through the weekend, bringing heavy rain at low elevations Thursday to Friday, according to the National Weather Service.

Agencies warned residents to heed caution even in what might appear to be shallow water flooding roads. Capitola police issued notice for residents in low areas about possible flooding at least through Thursday.

Sand and bags are available at Capitola City Hall. Capitola residents can take up to 10 bags, police said.