MARENGO, Ill. (WLS) — Five people were injured, three critically, in a north suburban crash during “whiteout conditions” on Sunday morning, fire officials said.

The Marengo Fire & Rescue Districts and Union Fire Protection District responded to a two-vehicle crash near North Union Road and Route 176 just before 9:30 a.m. At that time, a bystander had already started performing CPR on someone involved in the crash.

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Roads were covered in snow with “whiteout conditions,” fire officials said. First responders initially requested a medical helicopter, but it was unable to respond due to the weather conditions.

Fire officials said five people were transported to local hospitals. Three people were in critical condition, one was in serious condition, and another suffered minor injuries.

What led up to the crash was not immediately clear. The McHenry County Sheriff’s Office is investigating.

Officials did not immediately provide further information.

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