Brutal cold returns to US Midwest, hits flights

CHICAGO — Severely cold weather in the U.S. Midwest caused more than 500 flights to be cancelled at Chicago's two main airports Monday.

A weather pattern that's driving Arctic air south is keeping temperatures far below freezing into Tuesday.

Chicago Public Schools called off Monday's classes for its nearly 400,000 students.

In Michigan, highways closed as snow and subfreezing temperatures played a role in multiple crashes Sunday. At least three people died over the weekend because of weather-related accidents.

"This is similar to what we had three weeks ago" in terms of life-threatening conditions, said Sarah Marquardt, a National Weather Service meteorologist. "With wind chills in the minus 30 to minus 40 range, you can get frostbite within 10 minutes on exposed skin."

Residents of Minnesota and Wisconsin faced similar if even somewhat more severe weather.

Companies offering delivery services were inundated with business as Artic air blasted the central U.S. on Monday for the second time in weeks, disrupting the lives of even the hardiest Midwesterners.

The brutally cold weather has brought a spike in business for GrubHub Seamless, a company that lets users order food online from restaurants and have the food delivered.

"Across the board, restaurant and delivery drivers are dealing with an influx of orders," Allie Mack, a spokeswoman for the company said in an email.

Not only that, but people seem to appreciate the drivers more, with Mack saying that during the Polar Vortex earlier this month, tipping was up by double digits in Detroit, Cleveland, Minneapolis, Chicago. And, for some reason, deliveries of buffalo chicken sandwiches jumped 37 percent.

"You figure people are probably being more generous to their drivers because their drivers are the ones braving the conditions while you're on your couch in your pajamas," Mack said. (AP)