At least one person has been killed in severe flooding in Redding, Mayor Mike Littau said on social media Sunday night.

Police and Fire Department crews have been conducting water rescues, he said, adding that the Red Cross has set up a shelter for any evacuees at the Congregational church at 2850 Foothills Blvd.

The National Weather Service said Sunday night that "life threatening flash flooding" was occurring in south/central Shasta County, including downtown Redding, Interstate 5, and State Route 299. A flash flood warning expired at 10:45 p.m. local time. "NEVER drive through flooded roads!" the service added.

Separately, an evacuation warning was issued Sunday as heavy rain caused the South Yuba River to rise in the Cisco Grove area of Placer County, officials said.

The Truckee Fire Protection District said at 2 p.m. that they were working on a "unique rescue" on Donner Summit.

Crews said a home along the South Yuba River swelled, leaving the people inside the home unable to leave after significant rainfall. 

No injuries were reported, and the Placer County Sheriff's Office said nine people made it out safely.

"This is a good reminder that water levels can change as the rain continues," the fire department said. "Avoid being in or near the water. Do not try to attempt to drive or wade through floodwaters."

Placer County evacuation warning

The Placer County Sheriff's Office said water levels of the South Yuba River rose near Hampshire Rocks Road, between Donner Pass Road and Cisco Road. Deputies have issued an evacuation warning for the area. 

"Additional flooding may occur with little notice," the sheriff's office said. "Residents should prepare now by gathering essential items, monitoring official alerts, and being ready to move to higher ground if conditions worsen."

The National Weather Service has the Donner Summit area under a slight to moderate risk of excessive rainfall. 

The area is also under a flood watch until Dec. 26.