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 all 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.

“We’re applying those lessons as we move forward,” she said.

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

City Clerk Trisca Dix told The Associated Press that 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.

Many people moved their belongings to the upper levels of their homes and built sandbag barriers before evacuating, he said.

“We’re just trying to be more proactive than we were in ’08, trying to save as many homes as we can,” Yock said.

In Cedar Falls, about 55 miles (90 kilometers) upriver from Cedar Rapids, Lynn Hoth was among a group of volunteers who spent Friday filling sandbags and building flood barriers.

“Last time, we were an island for three days and we couldn’t get in or out,” Hoth told KCRG, referring to the catastrophic flood of 2008, which caused billions of dollars in damage. This time around, “we’ve had notice, so that’s good, and people help each other.”

In southeastern Minnesota, roads were reopening Saturday as floodwater receded. But north of Minneapolis, parts of Highway 169 remained closed in both directors because of flooding.

Parts of southern Minnesota will remain under a flood warning until Monday morning. In central Wisconsin, a flood warning was issued for the Yellow River at Babcock until Sunday morning, but the river wasn’t causing any major problems, according to National Weather Service meteorologist Rick Mamrosh in Green Bay, Wisconsin.

In southwestern Wisconsin, the Kickapoo River appeared to have crested and the Black River was on its way down. But the Yellow River is still rising and may reach major flood stage Sunday evening, said Clint Aegerter, a meteorologist at the weather service’s office in La Crosse, Wisconsin. The Mississippi River at La Crosse may crest at minor flood stage around 4 p.m. Monday, he said.

Still, the weather service said storms Saturday night into Sunday would bring more rain to the area.

Another meteorologist in the La Crosse office, Todd Rieck, said a half-inch to 1 inch of rain is possible in southwestern Wisconsin, southeastern Minnesota and northeastern Iowa late Saturday through Sunday.

“If you even got an inch in most locations, it would result in further flooding problems,” Rieck said. “There’s no place for the water to go.”

In Cedar Rapids, officials said those residents who have been asked to evacuate should plan to remain out of their homes and businesses for up to a week. A curfew was also to go into effect Sunday beginning at 8 p.m.

They had some good news, too: The Cedar River is expected to crest at 24.5 feet on Tuesday, which is nearly a foot lower than they earlier projected.

Fire Chief Mark English asked the curious to stay out of the flooded areas, noting that some heavy equipment used to build earthen dams and erect flood barriers has been hindered by gawkers. He said an estimated 1,500 properties near the river are expected to get at least some flooding.

Iowa Gov. Terry Branstad and other state officials were set to tour flood-damaged areas Saturday in the Cedar River basin.