LODGE GRASS, Mont. – Rain-swollen rivers that have swamped Montana towns could keep flooding the region for another month or more as melting mountain snow delivers a second slug of water to the soggy Northern Plains.
Heavy rains are forecast through the holiday weekend. Warm weather after that is expected to kick off the melt of snows that in some areas are twice as deep as average.
Even with rivers already raging from record rainfalls, authorities have started dumping massive volumes of water from low-land reservoirs to get ready for the annual spring rise.
Those releases are predicted to flood homes downstream in the Dakotas, and possibly in Iowa, Nebraska, Kansas and Missouri.
"There is going to be record flooding all along the Missouri River," said Paul Johnson, director of the Douglas County, Neb., Emergency Management Agency. "This isn't going to return to normal anytime soon."
In Montana, the state's famous rivers and streams — swollen to 10 times their usual size in places — continued to carry a torrent of damaging debris through small towns and over roads Friday.
Cresting waters have broken through barriers and left hundreds of homes drenched in muddy floodwaters.
Eroded roads in rural areas left some residents stranded at their homes. State and local officials said they were making sure adequate food and water were delivered where necessary.
After authorities declared emergencies in 51 Montana counties, towns and Indian reservations, the governor toured some of the hardest-hit areas Friday.
"The people need help, not only in this area but all down the road. Some people lost everything," Kathryn Old Crow, 73, told Gov. Brian Schweitzer after his helicopter touched down near Lodge Grass, a remote Crow reservation town near the Wyoming border.
Hundreds were displaced after parts of the reservation got more than 8 inches of rain over just a few days this week. That's more than half of what the arid reservation receives on average over an entire year.
More rain was forecast for a Memorial Day weekend that will be hard on travellers, and not just because of bad weather. Dozens of roads and highways were closed around the state, including a 170-mile stretch of US-12 from Harlowton to Forsyth.
Officials warned that many campgrounds and fishing access sites also would be closed.
"We are going to be in floods not just here but all over Montana for the next 30 days," Schweitzer said during his tour of flooded areas.
And as all that water spills from high elevations toward the Great Plains, the U.S. Army Corps of Engineers said it has no choice but to continue unprecedented releases from brimming reservoirs. Dams built decades ago to contain dangerous floodwaters were now being used to release a carefully controlled torrent.
In Missouri and Nebraska, the river was already spilling over its banks and soaking low-lying farmland. More flooding was predicted as releases from swollen upstream reservoirs were expected to reach historic levels.
"We have gotten about a year's worth of rain in Montana in the last month," said Monique Farmer, spokeswoman for the corps' Omaha, Neb., district. "It's just crazy. It's been an unusual year."
Officials said water is encroaching on cities such as Fort Calhoun, Neb., and Sloan, Iowa — where residents built a temporary levee out of sandbags to help protect a dozen homes near the river.
The corps predicted 2011 could be one of the wettest years on record in the Missouri River basin, with flooding carrying on into July.
South Dakota officials decided to build emergency earthen levees on each side of the Missouri River in an attempt to protect homes in Pierre and Fort Pierre from floodwaters.
But South Dakota Gov. Dennis Daugaard said more releases from dams could flood some homes before work on the levee system can begin
"We believe the levee construction is certainly very good news, but some areas will be inundated even as the levees are being constructed," Daugaard said.
In Wyoming, Gov. Matt Mead said Friday he was deploying more than 100 Wyoming National Guard soldiers as more snow was predicted to fall this weekend and the state's huge mountain snowpack was expected to begin melting in earnest next week. Three Wyoming counties already have requested Guard help.
Unseasonably cool weather could bring a small amount of respite in Montana over the holiday weekend by delaying the mountain snow melt. But Montana Disaster and Emergency Services Division chief Ed Tinsley warned the reprieve could be brief.
Weather officials said another 1 to 2 inches of rain was forecast over the weekend for eastern Montana.
The additional precipitation could cause the Milk River in northern Montana to rise another foot, putting it 6 feet beyond flood levels, said Bill Martin, National Weather Service meteorologist.
The Montana Department of Fish, Wildlife and Parks warned anxious anglers that the state's blue-ribbon trout streams are now carrying "all manner of dangerous debris."
The agency closed access to the rivers in many places and warned those who try to brave the floodwaters to be prepared.
Schweitzer and U.S. Sen. Jon Tester toured waterlogged communities to gauge the damage. Several dozen homes in the central Montana town of Roundup remained underwater.
Roundup emergency officials said the closure of U.S. 12 cut off road access to the town from the west and east. The only way into Roundup by road was from the north because U.S. 87 south of town also was shut down.
Montana's governor also planned to travel north to Lewistown, where floodwater had swamped parts of town and forced road closures.
On the Crow Reservation, 200 damaged homes had already been tallied. And Chairman Cedric Black Eagle expected that figure to rise.
Donations of food and other necessities were coming in to the tribe, but officials said more was needed. Also damaged by the high waters were irrigation systems, roads, bridges and other infrastructure.
"It will be six months to a year before things are back to normal," Black Eagle said.
About 300 reservation residents fled north to Billings to take temporary refuge on a college campus where the Red Cross set up a shelter. Crews worked Friday to restore full pressure to the reservation's water supply.
Associated Press writers Stephen Dockery in Helena, Josh Funk in Omaha, Neb., Chet Brokaw in Pierre, S.D., Bob Moen in Cheyenne, Wyo., and Maria Sudekum Fisher in Kansas City, Mo., contributed to this report.