(Adds details on records, evacuation and details of flood damage)
March 18 (Reuters) - Flooding that killed three people in Nebraska and Iowa has cut roads to a nuclear power plant and inundated a significant portion of a major U.S. Air Force base, while more of region's residents faced the possibility of evacuation on Monday.
The floods, which prompted each state's governor to declare a state of emergency, are the result of last week's "bomb cyclone" winter storm, which blew in from the western Rocky Mountains. At least one person was missing after hundreds of weekend rescues.
The floodwater forced the operators of the Cooper nuclear plant, near Brownville, Nebraska, to fly in staff and supplies by helicopter, and covered one-third of that state's Offutt Air Force Base, near Bellevue, home to the U.S. Strategic Command. The nuclear plant continued to operate safely and was at full power, its operator said.
The National Weather Service reported some of the region's larger rivers were running at record high levels, causing levee breaks. Some small towns and communities have been cut off by floods while others found themselves short of fresh drinking water.
Streets in Lincoln, Nebraska, were barely visible as high water surrounded homes, cars and trees, according to photos released to Reuters by state authorities. Elsewhere in the state, one highway near Waterloo was submerged, and piles of debris and damaged roads were visible in Niobrara.
Floodwater climbed up the sides of buildings at Camp Ashland, an Army National Guard facility in Ashland, Nebraska.
The NWS reported that temperatures across the hardest-hit areas will reach above 50 degrees Fahrenheit (10 C) through midweek.
That would speed the pace of snow melt across the region and contribute water to already swollen rivers, the NWS said, possibly forcing more evacuations in communities along the Missouri River on the Nebraska and Iowa border, as well as along the Elkhorn and Platte rivers in Nebraska.
"There could be issues across portions of Nebraska and Kansas for the next seven days," NWS meteorologist Jim Hayes said.
The Missouri River was expected to crest at 47.5 feet (14.48 m) on Tuesday, breaking the previous record in 2011 by more than one foot, according to Nebraska Emergency Management Agency (NEMA). The Elkhorn River crested at 24.6 feet on Saturday, breaking its previous record in 1962 by 5.5 feet.
More than 600 Nebraska residents were evacuated and taken to American Red Cross-operated shelters, NEMA reported on Sunday.
Nebraska Governor Pete Ricketts, who declared a statewide emergency last week, said on Monday that emergency officials have rescued at least 300 people but that at least one person was missing.
At Offutt Air Force Base, 30 buildings had been flooded by up to 8 feet of water and 30 more structures had been damaged, according to reports by the Omaha World-Herald, citing a base spokeswoman. Base officials did not respond to a request for comment.
The weather was blamed for three deaths, including one person who died at home after failing to evacuate, and a man swept away while trying to tow a trapped car with his tractor.
In Iowa, one man died after he was submerged in floodwater on Friday in Riverton, according to the Fremont County Sheriff's Office. (Reporting by Gina Cherelus in New York and Rich McKay in Atlanta; editing by Scott Malone and Steve Orlofsky)
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