Chicago commuters, there's no other way to put this: Your drive Friday is going to be a bear.
A narrow band of very heavy snow will hit the United States' third largest city by population beginning Thursday night. Schools will be closed as millions see accumulations of 8 to 14 inches by late Friday.
"Travel will be very difficult to impossible at times, including during the morning commute," the National Weather Service said in a winter storm warning.
The snow will linger into Saturday, and a lighter round is likely Sunday.
Detroit will get a snow dump of its own: The forecast is for 6 to 9 inches. It, too, has closed its schools.
Chicago officials say they are ready. Trucks, plows and tons of salt are in position, they said at a Thursday afternoon news conference.
"Make no mistake about it: This is a heavy snow, heavier than we have seen in a number of winters," said Mayor Rahm Emanuel. "Now, Chicago is used to this. On the other hand, over the last winters we haven't had a snow at this level. And it is not just one night, it is going to go through the weekend."
Chicagoans are a hardy bunch, but a foot of snow is still a big deal. From 1884 to 2018, Chicago has had only nine days with 12-plus inches of snow.
Residents weathered 20 inches over two days in February 2011. A storm in February 2015, logging in at 16.2 inches, was the last time Chicago had more than 10 inches of snow in a single storm.
Chicago and Detroit flight cancellations for Friday were on the way up, according to tracking website flightaware.com. By Thursday evening, more than 600 flights were canceled to and from the two cities.
To the east, snow emergencies have been declared in many metro Detroit communities, according to CNN affiliate WDIV. Michigan State Police said "snowmageddon" was approaching.
"Please remember with all of the school closings that there will be lots of kids playing in the snow and they may not be watching! Drive carefully!" the agency tweeted.