cleans up@ (Recasts first sentence with struggling Nebraskans, adds comments by Nebraska resident and governor, details on Missouri and Mississippi preparations, changes dateline from BROWNVILLE, Neb.)
VALLEY, Neb., March 20 (Reuters) - Nebraskans struggled on Wednesday to clear the wreckage left by deadly floods that caused an estimated $1 billion in damage, while emergency officials farther south kept a wary eye on the Missouri and Mississippi rivers as the disaster threatened to spread.
Floodwaters resulting from a late-winter storm last week and warming spring weather that melted snow quickly this week inundated a large swath of Midwestern farm states Missouri, Nebraska and Iowa along the Missouri, North America's longest river. States of emergency have been declared in all or parts of the three states.
Missouri officials stacked sandbags along major waterways and closed highways near the rising Missouri River, and Governor Mike Parson urged residents to be careful near the river.
The floods have killed four people in Nebraska and Iowa since the weekend and officials warned the physical damage toll would rise as receding waters revealed more devastated roadways, bridges and homes.
More than 2,400 homes and businesses were destroyed or damaged in Nebraska, with 200 miles (322 km) of roads unusable and 11 bridges wiped out, Governor Pete Ricketts told a news conference.
In Valley, Nebraska, outside Omaha, Pete Smock was working to clear deep mud that surrounded his home and construction business.
"Devastation is everywhere. I haven't seen anything like this in my lifetime," said Smock, 42. He had rented heavy equipment to fill deep holes cut by the floods with gravel and repair driveways leading to his office and garage.
"I can't work a day before I clear this up," Smock said.
Mississippi, where some 40 counties were still recovering from floods early in the month, declared a fresh state of emergency.
The National Oceanic and Atmospheric Administration also predicted major flooding for parts of Kansas, Missouri and Arkansas.
In Arkansas, emergency officials said they were monitoring the situation but did not believe flooding would reach crisis levels.
The National Weather Service expects warm weather in the north-central United States to continue into Thursday and Friday, triggering more accelerated snow melt, meteorologist Rich Otto said in a phone interview.
'STOP! TURN AROUND!'
Farmers scrambled to move their harvested grains before flooding destroyed them.
In northwestern Missouri, where waters were still rising and rivers had not yet crested, farmer Howard Geib, 54, had a close call.
"I was driving out to get one more load of corn from the bins when the levee broke, and there was a wall of water coming at me," said Geib, 54, whose farm is near the town of Craig.
"I was on the phone with my son-in-law, who was driving out to help, telling him, 'Stop! Stop! Turn around!"'
Authorities said they had rescued nearly 300 people in Nebraska alone, with some rivers continuing to rise.
The flooding killed livestock, destroyed grains in storage and cut off access to farms because of road and rail damage.
The tiny village of Rulo, Nebraska, across the Missouri from Craig, has been drawing a small crowd of onlookers to see the deluge, said Kelly Klepper, owner of Wild Bills bar.
"We're kind of a tourist attraction right now," Klepper said by phone. "People that don't normally come to Rulo have been coming to Rulo to check out the water."
OVER $1 BILLION IN DAMAGE
Nebraska's Ricketts estimated on Wednesday that the floods caused at least $439 million in damage to public infrastructure and other assets, and $85 million to privately owned assets.
Ricketts also estimated flood damage for the state's agricultural sector at nearly $1 billion, with about $400 million in calf losses and $440 million in crop losses.
Roads leading to the Nebraska Public Power District's Cooper nuclear plant near Brownville were engulfed by floodwaters from the Missouri, but the facility was still operating safely at full power on Wednesday.
Offutt Air Force Base near Omaha, which houses the U.S. Strategic Command, remained heavily flooded, though base officials said on Twitter the facility was still "mission-capable." The Strategic Command's mission includes defending against and responding to nuclear attacks.
"We're looking for it to recede by late tomorrow," Drew Nystrom, a spokesman for the base, said on Wednesday. "It's gonna take a concentrated effort and many months to get everything back to normal."
(Reporting by Humeyra Pamuk, additional reporting by Gina Cherelus in New York, Rich McKay in Atlanta, Jarrett Renshaw in Philadelphia, P.J. Huffstutter and Mark Weinraub in Chicago and Dan Whitcomb in Los Angeles Editing by Scott Malone and Matthew Lewis)