FAIRBANKS—Heavy flooding has again forced the Dalton Highway to close, severing the only thoroughfare to Alaska's oil-producing North Slope.

Milepost 394 to milepost 403 is the most severely affected section of road. More than 2 feet of water rushing over the road in some locations has caused washouts and surface erosion, according to the Alaska Department of Transportation and Public Facilities.

A notice sent out by the department announcing the closure described flooding as "extreme."

The road is officially closed between milepost 375, about 40 miles south of Deadhorse, and milepost 414, the end of the road. The larger closure was implemented to give crews staging areas for equipment and materials in anticipation of reconstruction.

Hydrologists with DOT and the University of Alaska Fairbanks expect water levels to crest later in the week, and there's no tentative date to reopen the road, DOT Northern Region spokeswoman Meadow Bailey said.

Bailey said road conditions depend on "a lot of variables" and the closure "definitely could be longer than four days." Truckers started voicing concerns about road conditions to DOT on Saturday, Bailey said.

However, the closure did not come unexpectedly. Since ice and water closed the road in March, prompting Gov. Bill Walker to announce a disaster declaration, the department has been preparing for ice overflow from the Sagavanirktok River to melt and again flood the road.

The declaration allowed DOT to hire contractors to assists with reopening the road and to help keep traffic flowing. Crews will be installing culverts and building berms to divert water and protect the road surface from erosion.

Bailey hoped breakup would arrive slowly, but recent temperatures in the 60s rapidly advanced the melting process.

"(We) knew there would be flooding. Be prepared and be able to make repairs as fast as possible," Bailey said of the department's response.

Bailey said no trucks have been reported stranded.

Contact staff writer Robin Wood at 459-7510. Follow him on Twitter: @FDNMcity