A stretch of east metro freeway through Oakdale that normally accommodates up to 87,000 vehicles a day won’t reopen until at least Friday and probably later, as crews determine whether shifting ground caused a massive water spill under Interstate 694, officials said Monday.

Once the city completes its work on an underground water line, the Minnesota Department of Transportation will begin restoring the freeway’s substructure and might not reopen I-694 until next week, said spokesman Kevin Gutknecht.

“I don’t want to give a time until we’re really sure. We realize this is inconvenient to the public, but we want to get it fixed right,” he said.

City workers suspect that an environmental factor such as heaving or shifting caused the water main break, said Oakdale police spokeswoman Michelle Stark. An investigation is continuing into the cause, she said.

The damaged area is a few miles north of where I-694 intersects with Interstate 94 between Oakdale and Woodbury.

After MnDOT closed both directions of I-694 on Sunday, massive traffic backups occurred. Officials initially shut down a 2-mile stretch Sunday between 10th and 34th avenues and later shut down 5 miles of the freeway Sunday night.

That sent motorists on miles-long detours along Hwy. 36, Interstate 35E and I-94. Several Oakdale arterial streets, such as Century and Hadley avenues, saw traffic jams Monday as drivers sought alternate routes.

Bill Holton, who commutes from his Woodbury home to White Bear Lake, used McKnight Road as his highway alternative. His temporary commute took an extra 10 minutes.

“There are probably people who had it a lot worse,” he said. “I can imagine it’s not very pleasant for a lot of people. It’s something I think everybody hopes will get fixed pretty quickly.”

Metro Transit officials warned about bus delays, especially during morning and evening rush hours, and riders were reporting delays of about 20 minutes.

Oakdale city workers were able to shut off the 12-inch water line and restore service to all but 10 households on Monday as they excavated to determine the specific cause of the leak. The main is fed by two of the city’s four water towers, said Shawn Nelson, Oakdale’s utility superintendent.

He described erosion from the leak as a washout rather than a sinkhole, as previously reported. A hole was visible in the median between the northbound and southbound lanes.

The ground under the freeway near 15th Street began eroding early Sunday after 1.5 million to 2.5 million gallons of water began pouring from the 53-year-old pipe, forcing MnDOT to close the freeway for almost the entire north-south length of Oakdale.

A resident who saw water accumulating about 9 a.m. Sunday called police. Equipment sensors at the Oakdale Public Works department also flagged the problem.

Flooding created the washout under the southbound lanes just north of the 15th Street N. overpass. The driving surface remained intact but wasn’t safe for vehicles because of the washout below it, Gutknecht said.

“We are grateful nobody was injured and glad damage was not greater,” said Mayor Paul Reinke.

After the magnitude of the leak was discovered, 35 households had no service and another 6,000 had pressure fluctuations, Nelson said Monday.

The cost of repairs won’t be known for several days, MnDOT and Oakdale officials said.