GRAND FORKS -- A Midwest heat wave has put a Grand Forks bridge partly out of commission.

City staff on Sunday, July 5, closed two lanes of traffic on the Columbia Road railway overpass, a restriction designed to keep motorists away from a spot where interlocking sets of metal teeth on the bridge’s northerly end had pushed up, creating a small but unexpected obstacle. Grand Forks police asked the public on Sunday to slow down when crossing the bridge and suggested finding alternate routes through that part of the city.

The concrete bridge has a joint on either approach that gives it room to flex during seasonal extremes. In cold weather, the concrete contracts, creating small gaps between each joint. In hot weather, it expands, pushing the bridge segments closer to one another. Over the weekend, the heat caused those segments to push together so tightly that the bridge began to buckle, which created the small ridge across the roadway.

“It’s an older joint, so I guess it’s starting to show its age,” city engineer Al Grasser said Monday. “But it should come back when temperatures cool down and things settle down.”

This July has been a relatively warm one: Daily high temperatures have hovered at about 90 degrees, which is about 11 degrees hotter than normal, according to National Weather Service Data.

A city engineering contractor is set to inspect the bridge joint and determine if it needs to be fixed and how to fix it, if required.

“Normally, these things, they open and close pretty regularly,” Grasser said of the bridge joints.

Grand Forks had a similar problem about 10 years ago, he said, which required the city to rebuild the bridge’s southerly joint. Grasser said he wasn’t aware of any similar damage during this year’s heat wave, but wouldn’t be surprised if that was the case.

Temperatures had subsided slightly since the weekend. The National Weather Service in Grand Forks predicted a high of 80 degrees on Monday and did not predict a high greater than 87 degrees for the remainder of the work week.