Illinois State Police say severe winter weather conditions caused two car crashes in March that involved a grand total of 34 vehicles on a Chicago expressway. Both of the pileups occurred in highway express lanes on the city’s North Side.

Multiple factors can contribute to accidents like these, including under-inflation and improper tires. A tire can lose up to 50% of its inflation pressure and still appear normal, but that was unfortunately not the cause of these two massive crashes.

Winter storm Stella pummeled a good portion of the nation, sweeping snow from the Midwest to the Northeast. It came after an unseasonably warm stretch, making it all the more shocking for those affected by the severe winter weather.

In addition to dumping one to two feet of snow in most places it passed over, Stella managed to ground more than 6,000 flights and take out power for almost 250,000 customers from Virginia northward. The storm was officially declared a blizzard by the time it reached Massachusetts sporting 70 MPH winds.

It was easily the worst storm in a season that had been relatively mild in the Northeast, and despite many people’s best efforts, it still caused multiple issues, pileups included.

The chain reaction of accidents on the Kennedy Expressway occurred at approximately 10:15 PM between Division Street and North Avenue. Chicago firefighters rushed seven individuals to local hospitals for treatment, including one man who was transported in serious condition.

There are approximately 110 million emergency room visits made annually, and fortunately for the other six people transported to local hospitals in these crashes, their injuries were minor. Despite other minor bumps and bruises reported, at least 23 people refused immediate treatment at the crash site.

It took upwards of three hours for officials to clear all of the cars away from the crash site. Vehicles involved included Uber cars, minivans, and even an Illinois State Police cruiser. It’s possible to find car carpets for models dating all the way back to the 1940s, but it’s uncertain what repairs the vehicles involved will need. Police report the state trooper, though in their car at the time of the crash, was unharmed.

The crash site was cleared completely by 2 AM and it was quickly confirmed that the cause was weather-related. Cars attempting to slow down simply kept sliding, as the weather provided extremely slick surfaces.

“We were all going too fast,” one driver told NBC 5. “I don’t know if the express lanes should have been open.”

Chicago wasn’t the only accident scene, either. A 16-year-old girl was killed when she lost control of her vehicle and hit a tree during the winter storm in Gilford, NH. Accidents of a similar nature occurred throughout the Northeast during the storm, making it one of the most devastating in the last year for the region.