Fierce floodwaters in eastern Nebraska have seriously impacted two of the state’s military facilities, Offutt Air Force Base and the Nebraska National Guard’s Camp Ashland training base.

Offutt’s lone runway has been closed until 1 p.m. Tuesday, according to a notice to airmen issued by the Federal Aviation Administration.

Offutt airmen are filling 20,000 sandbags as water from the adjacent Missouri River creates “significant pooling” in the southeast part of the base, 55th Wing Commander Michael Manion said on his official Facebook page.

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“We are relocating critical missions away from that area of the base and are bolstering water defenses,” Manion said in the post.

The area around the base lake has been evacuated, as has a nearby campground, base officials said.

“The next 72-96 hours will be critical as the flow of water peaks,” Manion said.

The base is home is the headquarters of U.S. Strategic Command and the 55th Wing.

For the second time in four years, the Guard’s Camp Ashland, on the banks of the Platte River east of Ashland, has been swamped by floodwaters.

Rising waters forced the evacuation Wednesday of 225 soldiers from Nebraska and several neighboring states who were taking classes at the site, said Spc. Lisa Crawford, a Nebraska National Guard spokeswoman. They were taken to another base in Mead, then moved again to Omaha after waters began to cross roads leading to that facility. No one was injured.

Crawford said soldiers assigned to Camp Ashland moved vehicles to higher ground and placed items in offices on top of desks.

They also closed floodgates installed after a flood on May 7, 2015 — classified at the time as a one-in-1,000-year event — that caused hip-deep water in some of the base’s 58 buildings. The Guard spent $3.7 million installing floodgates on some buildings, rebuilding others on stilts and adding additional flood-control measures.

It may have been for naught.

Crawford said the flooding was more widespread and more buildings were affected than in 2015. She said soldiers have opened the floodgates only to inspect a single building, a maintenance building where several people work. The water was 5 feet high inside.

“It appears (the floodgates) were not very effective, because the sheer amount of water was much greater,” Crawford said. “This is the first time they’ve really been tested.”