Traffic resumed on DuSable Lake Shore Drive after a bridge over the Chicago River was closed for nearly 4.5 hours Wednesday because of what city officials said was a heat-related issue.

A Heat Advisory is in effect for the Chicago area from noon through 9 p.m. Wednesday.

ABC7 Accuweather meteorologists said high humidity will be in the area throughout the day. Heat index values are forecast to be over 100 by around noon.

The disruption on DLSD Wednesday began during a scheduled bridge lift, leaving motorists stranded and forcing city crews to divert traffic. Cyclists and pedestrians were also affected by the closure.

Tom Renaud, who left work for a lunchtime bike ride, said he was caught on the south side of the bridge after crossing from the North Side.

"They said it was gonna be 15 minutes, so I weasel my way into the city and down through Grant Park and have been riding for the last hour and a half," Renaud said.

Some drivers on DuSable Lake Shore Drive were delayed significantly longer as crews worked to resolve the problem. Cyclist Pete Conroy said the closure disrupted his plans.

"I had an appointment this morning and yeah, came up on this," Conroy said.

The Chicago Fire Department deployed a boat to spray water on the bridge in an effort to cool the steel and help it contract.

In a statement, a spokesperson for the Chicago Department of Transportation said: "The issue during today's scheduled bridge lift was heat-related. Thermal expansion caused by extreme heat is not uncommon, and crews are continuing to make the necessary adjustments to safely reopen the bridge to traffic."

The closure also affected people traveling to Chicago's lakefront. Jose Fox said he suspected the extreme temperatures were responsible when he arrived at the bridge.

"I just rolled up and I thought it was something with the heat. Being so hot the bridge locked up or what not. Turn out you were right. Yeah that's what happens in Chicago when it gets cold it freezes and when it gets hot it burns," Fox said.

The bridge lift was not part of the city's regular seasonal bridge lift schedule, when boats leave and return to Chicago harbors in the spring and fall. According to the report, the lift was conducted as a special request that the Chicago Park District is required to honor.

The Chicago Department of Transportation said similar incidents have occurred occasionally in the past.

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