"It is a horrible human tragedy to watch this," he said.

Heavy snow

Heavier-than-average winter snows and spring rains have swollen the river, creating the flood threat which reached other areas of North Dakota and Minnesota.

Some water was seeping through the ground in several different locations.

US army engineers have constructed a second dyke behind the breached one.

People living near the cracked dyke and seepage locations, including a senior's residence, have been evacuated by the emergency services.

Some of Fargo's roads were closed down due to the riding floodwaters, hampering the emergency response and residents' attempts to leave.

At about 14 metres the dykes are a 30cm higher than the forecast crest.

"We're hoping against hope... If the dyke holds and the crest doesn't go over 43 feet [14 metres], I'm okay," Nick Sinner, a Fargo resident, said.

The Red River is susceptable to flooding because as it flows north to Canada it freezes, pushing water over its low banks and onto the area's large flat landscape.