CEDAR RAPIDS, Iowa —Volunteers filled sandbags and homeowners began moving things out of their basements on Saturday, and one small town evacuated about 100 homes in preparation for flooding along the Cedar River in Iowa.

The river is expected to crest Tuesday in Cedar Rapids, Iowa’s second largest city with a population of about 130,000. But with more rain expected Saturday night, officials there warned people to evacuate downtown areas of the city near the river by 8 p.m. Sunday.

“We have emergency personnel that can help you if needed,” Cedar Rapids Mayor Ron Corbett said Saturday. “They’ll risk their lives for you. But we don’t want them to risk their lives.”

At the Cedar Valley Montessori School in downtown Cedar Rapids on Friday, about 100 volunteers from area high schools helped move the school equipment above the ground floor.

Stacy Cataldo, head of the Montessori school, told television station KCRG that many remember how flooding damaged the school in 2008 and don’t want that to happen again.

Upriver in the town of Palo, about 100 homes in low-lying areas were evacuated Saturday.

City Clerk Trisca Dix said the mandatory evacuation in the town of about 1,000 took place Saturday afternoon before the river was expected to crest Sunday night at 24.5 feet.

Mayor Tom Yock told the Des Moines Register that volunteers and work crews scrambled Saturday to protect as much as possible of the town, which was devastated by record flooding in 2008.