A flash flood warning was issued for Long Beach and other parts of Southern California as heavy rain saturated the area for much of Thursday.

There was at least one report of someone being washed down the Los Angeles River because of the weather, but it’s unclear if it was a false alarm. Authorities weren’t able to find anyone who’d been swept away.

At around 12:30 p.m., the Long Beach Fire Department deployed rescue teams up and down the L.A. River after the L.A. County Fire Department received reports of a person possibly stuck in the river in Paramount.

An L.A. County Sheriff’s helicopter also hovered over the river looking for the person, but rescue crews weren’t able to find anyone and called off the search around 1 p.m.

Authorities also reported flooding in some low-lying areas and surface streets.

In Central Long Beach, Chittick Field on Pacific Coast Highway was under water—but it is designed as a flood control detention system. The field, developed in 2014, has a low-flow drainage system, a pump station and various stormwater treatment devices to capture and treat runoff.

The National Weather Service showed Long Beach Airport received close to two inches of rain on Thursday.

Prior to Thursday’s rain, Long Beach was already at 100 percent of normal for the rain year, which began on Oct. 1. The city had received 1.89 inches of rain through Wednesday, and on Thursday, the city received another 1.65 inches.

A rainbow is seen over one of the buildings in downtown Long Beach after a rainstorm in Long Beach December 6, 2018. Photo by Atira West