Hundreds of volunteers turned out in the U.S. state of North Dakota Wednesday to help national guard troops build sandbag barriers against the rising waters of the Red River, which continues to flood parts of the north-central U.S.
President Barack Obama declared North Dakota a federal disaster area Tuesday, which means the federal government will pay 75 percent of the cost of flood-relief efforts by state and local governments.
Floodwaters already have forced closure of many roads and bridges, and the water is expected to rise farther.
The flat terrain of the Red River Valley means floodwaters cover a wide area. Weather experts say the slow-moving water will take weeks to recede, because the soil is increasingly saturated.
Floods also are a problem in the neighboring state of Minnesota which, like North Dakota, borders the Red River on its route to Canada.
The region last suffered a devastating flood in 1997.
The Federal Emergency Management Agency, which is overseen by the U.S. Department of Homeland Security, says floods are one of the most common hazards in the United States.
Some information for this report was provided by AP and Reuters.