At least four tornadoes touched down in northern Illinois overnight as powerful storms swept across the upper Midwest, damaging rural communities and forcing thousands of soccer fans to seek shelter during the Copa America semifinal in Chicago, AP reported. The National Weather Service in Chicago said survey crews will investigate damage Thursday along three separate supercell paths. The number of confirmed tornadoes will likely increase, the weather service said. Officials also planned to request a survey of the damage by air, although a dense fog advisory was in effect for much of northern Illinois early Thursday. The storm system produced dime-sized hail in some areas and its high winds snapped trees, blew roofs off buildings and downed power lines. Firefighters responded to reports of people trapped in a house in Seneca after a tornado moved through the village about 70 miles southwest of Chicago Wednesday night.