Roughly ten inches of snow is expected to pile up across the Chicago area by Sunday morning in this winter’s biggest snowstorm.

Here’s a rundown of what you need to know whether you’re hunkering down for the whiteout, or if your boss doesn’t believe in snow days.

1. Schools — You might have a day off work, but odds are you won’t have a break from your kids. Hundreds of schools across the area, most notably Chicago Public Schools, canceled Friday classes before a single flake of snow fell on Thursday, according to the Emergency Closing Center. That includes most universities, too.

The Chicago Park District and Chicago Public Library facilities will be open if you’re looking for something to keep the little ones busy. The Adler Planetarium and Shedd Aquarium announced they would close for the snow, but as of Friday morning, the Field Museum appeared ready to open for business at 9 a.m. Better double-check their website before you make the trip, though.

2. Roads — Stay off them if you can — forecasters warned that drivers should be prepared for “significant” reductions in visibility. On Friday morning, the Illinois Department of Transportation said most roads in the Chicago area were already covered in ice and snow. As a result, hundreds of plows have been deployed across the city and expressways. If you do have to head out into the cold, make sure you’re driving with a basic safety kit.

IDOT announced Friday that the Kennedy Expressway’s express lanes would remain in the inbound direction until Friday night because of the snowfall. The express lanes will close at 9 p.m. for snow removal and will reopen in the inbound direction at 5 a.m. Saturday, when the normal schedule for the reversible lanes will resume.

3. CTA — Train and bus service was running smoothly Friday morning, but that could change with more snowfall expected throughout rush hour. Sign up for CTA alerts at transitchicago.com/updates, or follow the agency’s Twitter feed.

4. Metra — Bitter cold and piles of snow are causing havoc on the area’s main suburban transit lines. Metra cut 10 train routes on the BNSF line for Friday and adjusted the rest of its schedule in anticipation of the snow. They also dispatched 350 workers to shovel and salt platforms to keep up with the snow. On Friday morning, there were significant delays on the Rock Island, Milwaukee District West, North Central and Milwaukee District lines. Follow dedicated Twitter feeds for each Metra line for service updates:

For northwest Indiana commuters, the South Shore Line was expecting smooth operations. Sign up for email alerts at mysouthshoreline.com.

5. Flights — Airlines canceled hundreds of flights by Friday afternoon — 960 at O’Hare International Airport, and 315 at Midway International Airport. Delays at O’Hare were averaging 57 minutes, while delays at Midway were averaging less than 15 minutes. Check with your airline before you head out the door.

6. Forecast — As of 5:50 a.m. O’Hare had seen 4.6 inches of snowfall, while Midway had seen 4.8 inches by 6 a.m., the weather service said. Another inch or two could hit the area before noon, with up to four more inches expected between Friday evening and Sunday morning, as well as an additional inch of accumulation possible south of the city.