PIERRE, S.D. -- Flood-threatened neighborhoods of the South Dakota capital and its sister city across the swollen Missouri River largely emptied on Thursday as residents heeded calls to leave for higher ground ahead of the planned release of water from upstream dams.

Most of the approximately 3,000 people living in low-lying areas of Pierre and Fort Pierre had left homes, and others loading their belongings onto pickup trucks said they'd be gone by Gov. Dennis Daugaard's unofficial deadline of 8 p.m. No one was ordered to leave home ahead of Friday's planned dam releases, but it appeared few were willing to take their chances.

Water releases from the Oahe Dam were expected to increase slightly starting Friday morning and gradually rise until Tuesday, when water levels were projected to crest four feet higher, or about two feet below the levee top. Officials have kept the releases steady for nearly a week as people moved possessions to higher ground, placed sandbags around their homes and arranged for other places to live.

A similar release schedule was planned starting Saturday at Gavin's Point Dam upstream of Dakota Dunes, where the water level is expected to eventually rise another seven feet by June 14, again cresting about two feet below the tops of levees.

Daugaard and other officials said emergency earthen levees being built to protect the threatened areas should be completed in time to stop the rising water, but the governor warned people not to assume the levees would hold.

"While we hope the levees will provide protection for property, we urge that people not place themselves in danger or become complacent because a levee that is holding today is just holding today," Daugaard said.

In North Dakota, the Souris River at Minot crested Thursday after about 10,000 residents had been evacuated two days earlier.

In Montana, which has been by widespread flooding from heavy rains in the past couple of weeks, federal officials started ramping up water releases Thursday from Fort Peck Dam. Officials warned dozens of residents downstream their homes could flood when the peak is released in the next two weeks.

And in Missouri, Gov. Jay Nixon warned that the river there would rise to "unprecedented" levels. Residents in the northwestern part of the state, who have plenty experience dealing with floods, were preparing Thursday to either evacuate or help fill more than 75,000 sandbags.

Back in South Dakota, Ed Stutesman of Pierre said it was a sad day Thursday as he finished moving things out of his house.

"When you leave your own place, it's a different life. Thirty-five years I've lived here. Now I've got to go live someplace else," Stutesman said.

Steve Ellwein said he worked hard to develop a business and build a nice house on the river near Fort Pierre, but now he and his wife had to move out.

"I moved back in my old bedroom in my parents' house. I'm saying what's wrong with that picture," Ellwein said.

The mayors of Pierre and Fort Pierre said they have mostly finished protecting water, electrical and other utilities against the rising water. Law officers will soon start patrolling the emergency levees to make sure they do not leak.

"I think we're about as prepared as we can be," Fort Pierre Mayor Sam Tidball said.

Tidball urged people to stay away from the fast-flowing water in the river, noting that no lives have been lost yet.

"I urge everyone to continue working together and with law enforcement because things will get tense as the water rises," Tidball said. "We'll get through this situation, and we don't want any loss of life."

Kristi Turman, director of the state Office of Emergency Management, said 3 million sandbags have been sent to Pierre, Fort Pierre and Dakota Dunes in the week since officials learned releases would be increased substantially from the dams. About 900 troops from the South Dakota National Guard have helped the cities prepare for the water, she said.

Officials said levees in Dakota Dunes should be completed by Saturday.

Daugaard said if the levees hold after the water rises, residents might be able to return to their homes.

Eric Stasch, operations manager at Oahe Dam, said the levees, built by packing dirt to a height of about six feet, are designed to hold up against the rising water.