SAN DIEGO -- Free sandbags were being offered Thursday in anticipation of rainstorms forecast to continue through the weekend, but residents will have to provide their own sand.

Five San Diego fire stations and three lifeguard stands were offering 10 free sandbags per person, according to the fire department.

The five participating stations are No. 21 in Pacific Beach, No. 28 in Kearny Mesa, No. 29 in San Ysidro, No. 33 in Rancho Bernardo and No. 37 in Scripps Ranch. Participating lifeguard stations are in Ocean Beach, Mission Beach and Pacific Beach.

People can use beach sand to fill the bags.

Four erosion control centers have also been set up elsewhere in San Diego County, where residents can pick up sandbags, fiber rolls and seed mix.

Those centers are located in Valley Center, at 28565 Cole Grade Road; in Ramona, at 116 Fifth St.; in Fallbrook at 2551 Olive Hill Road; and Dulzura, 17304 Highway 94, according to the county Department of Public Works.

The county erosion control centers will be open from 10 a.m. to 5 p.m. through Saturday, according to the county.

San Diego County is expected to get as much as a foot of rain in the mountains by Sunday night, according to the National Weather Service. The valley areas could receive up to 3 inches.

Three storms are expected. The first two, Thursday and Friday, should be moderate, but a storm on Saturday is expected to bring heavy rain, chilly temperatures and significant snow on Palomar Mountain and Mount Laguna, according to the Weather Service.