CHICAGO — A wintry storm brought blizzard-like conditions to parts of the Midwest early Monday, grounding hundreds of flights and causing some road traffic chaos as commuters returned to work after the Thanksgiving weekend.

The Chicago Department of Aviation reported early Monday that average departure delays at Chicago’s O’Hare International Airport are 77 minutes, and the flight-tracking website FlightAware reported that more than 350 flights headed to or from the U.S. were cancelled.

Heavy snow was expected to continue through the early hours of Monday with up to a foot (30 centimetres) of snow expected in Chicago, including wind gusts of up to 50 mph (80 kph) likely to cause whiteout conditions, according to The National Weather Service.

Parts of southeastern Wisconsin, just north of Chicago, suffered a glancing blow from the storm, with about 9 inches (23 centimetres) of blowing and drifting snow.

On Sunday, Gov. Jeff Colyer declared a state of emergency after 2 to 14 inches (5 to 36 centimetres) of snow fell in parts of Kansas. The state Department of Transportation reported several road closures Monday, mostly in the extreme northeast, but said a stretch of Interstate 70 that had been closed on Sunday was reopened.

The National Weather Service said that 3 to 9 inches fell across northern Missouri on Sunday. The Missouri State Highway Patrol reported multiple fender-benders but by midmorning on Monday the Department of Transportation said all roads were opened. Flights were mostly on time Monday at Kansas City International Airport, one day after the storm caused widespread delays.