Heatwave grips parts of the US as Chicago tornadoes forced airports to halt traffic and residents were urged to seek shelter

There were no immediate reports of injuries but the storms forced authorities to ground all departures of commercial flights into O’Hare and Midway airports, the Federal Aviation Administration reported.

More than 300 flights in and out of O’Hare and another 32 in and out of Midway were canceled, according to FlightAware, while hundreds of people sought shelter at O’Hare.