"Corn gets the name corn sweats because corn puts out a lot of water vapor," Glisan said. "That's where we get these exceedingly high dew points and this oppressive heat, not because of corn, but corn ...

Chicago is sweltering under a heat dome with temperatures that feel like 110 degrees or higher. It's a reminder of the city's deadliest weather disaster 30 years ago. Ash-har Quraishi reports.