Floodwaters pouring out of the Souris River have already submerged homes and forced around 12,000 residents to flee as officials continued fortifying levees in Minot, North Dakota.

Workers and National Guardsmen were busy heaping dirt and clay on top of the earthen levees surrounding the town, but the mayor warned that more residents might need to secure their belongings and get away from the encroaching waters. A fourth of the town's residents have already been displaced, and the rising water level is on pace to shatter a record set in 1881.

We could have a really catastrophic type of event here, Minot Mayor Curt Zimbleman said. We will -- there is no doubt about it anymore. I think people have to understand if you were on the edge before you may not be on the edge now.

Many of the efforts were directed at protecting not only the infrastructure in North Dakota's fourth-largest city, but also Minuteman III nuclear missle silos that are currently shielded by pumps and sandbags. North Dakota Governor Jack Dalrymple warned that officials will need to begin releasing water from overflowing reservoirs, sending more water surging towards the town.

In two days' time, it will be a rapid, rapid rise, Dalrymple said.

Heavy rains and a larger than usual amount of melting snow have swollen the Souris River and filled reservoirs, making North Dakota the latest state to endure a record flooding season that has inundated communities from Montana to Iowa.