GRAND FORKS, North Dakota (Reuters) - The Red River was spreading out in a record swath across broad stretches of rural North Dakota and Minnesota on Tuesday and swelling toward a near-record crest in Grand Forks expected within three days.
The Red River and its tributaries have swamped expanses of land in the two states outside major cities, turning some spots into temporary islands that can be reached only by boat as the water flows north into Manitoba, Canada.
The river crested Saturday at Fargo, North Dakota, with minor damage. Permanent levees and flood walls are expected to protect Grand Forks from a projected 52-foot crest that would be the second highest on record, officials said Tuesday.
"The 52 feet forecasted by the Weather Service is not going to pose any problems for the City of Grand Forks," Grand Forks emergency manager Jim Campbell said.
The permanent protections were built after a record crest in 1997 above 54 feet breached defenses and flooded Grand Forks and East Grand Forks, Minnesota. The river forms the boundary of North Dakota and Minnesota.
The National Weather Service has projected the Red River will crest at Grand Forks from Thursday to Saturday as peak flows from its Red Lake River tributary reach the city.
Residents in subdivisions and rural areas north and south of Grand Forks were putting up sandbags on Tuesday, Campbell said. Three roads were underwater and 54 homes accessible only by boat in one section southeast of Grand Forks, he said.
"They are pretty much used to it," Campbell said of the subdivision, which was expected to be cut off for 10 days.
Forecasters expect little impact the rest of the week from precipitation in some parts of the Red River Valley.
"Yesterday was dry, today should be mainly dry," said Peter Rogers, a meteorologist with the Weather Service in Grand Forks. "There is a cold front coming through today, but any precipitation amounts should be fairly light."
He added, "The rest of the week should be pretty dry."
South of Grand Forks, the town of Halstad, Minnesota, was bracing for a crest within inches of a record Tuesday night.
North of Grand Forks and East Grand Forks, floodwaters spread across flat terrain, leaving communities such as Oslo, Minnesota, several miles from land in every direction.
Hundreds of National Guard troops from North Dakota and Minnesota have been sent to flooded communities across the two states to patrol dikes, watch pumping stations, route emergency traffic and respond to breaks in flood defenses.
Flooding has closed numerous county and state roads near the river as well as a 30-mile stretch of Interstate 29 that runs parallel to the Red River in North Dakota.
In Fargo and neighboring Moorhead, Minnesota, the Red River continued a gradual decline from Saturday's crest at 38.75 feet, which was the fourth highest on record. The river is expected to stay above 30 feet at Fargo for two weeks or more.
Some tributaries have been unable to flow into the Red River at these levels and instead were backing up and swamping miles of land in Cass County, which includes Fargo.
The flooding was expected to have a big effect on the amount of land farmers will be able to plant this spring, and has slowed grain movement in parts of the valley. A few weeks of dry and warm weather could allow farmers to resume grain and oilseed deliveries.
(Writing by David Bailey; Additional reporting by Doug Barrett and Rod Nickel; Editing by Greg McCune)