Several Illinois and northwest Indiana schools closed or delayed start times on Friday as dangerously cold temperatures descended on the Chicago area.
By Friday morning, dozens of schools reported late openings or full closures due to weather.
The entire Chicago area was under a Wind Chill Advisory beginning at 6 p.m. CST Thursday and lasting through 12 p.m. Friday.
Residents were urged to take extra precautions if going outside, as the advisory warned of wind chills at 20 or even 30 degrees below zero.
The cold wind chills could cause frostbite on exposed skin in as little as 10 minutes, the National Weather Service said.
Here's a look at some of the schools announcing closures as part of the winter weather:
Ambassador Christian Academy, Gary: Opening 2 hours late
Aspire, Hillside: Closed, employees to report
Aspire Charter Academy, Gary: Closed
Bailly Elementary School, Chesterton: Opening 2 hours late
Barack H. Obama Learning Academy, Markham: Closed
Beach Elementary School, Round Lake: 2 hour late start, no AM preschool session
Berger-Vandenberg Elementary, Dolton: Closed
Bible Baptist School, Highland: Closed
Blue Cap, Blue Island: Open, no buses
Blue Cap Workshop-ADT, Evergreen Park: Open, no buses
Burr Oak Academy, Calumet Park: Closed
Burr Oak School, Calumet Park: Closed
Calumet School, Calumet Park: Closed
Caroline Sibley Elementary, Calumet City: Closed
Catholic Charities - Diocese of Joliet ECSD, Joliet: Closed, employees to report
Center for Academics & Technology, Calumet City: Closed
Center for Alternative Learning, Calumet City: Closed
Charter School of the Dunes, Gary: Closed
Chesterton High School, Chesterton: Opening 2 hours late
Chicago Jesuit Academy, Chicago: Closed
Children's First Learning Center, Burnham: Closed 12:00 p.m.
Children's Place Learning Academy, Sauk Village: Closing early at 12 p.m.
City of Hammond Public Schools, Hammond: Closed
City of Hobart Schools, Hobart: Closed
Clifford Pierce Middle School, Merrillville: Opening 2 hours late
Col. John Wheeler Middle School, Crown Point: Opening 2 hours late
Coolidge Middle School, Phoenix: Closed
Crown Point Community School Corp, Crown Point: Opening 2 hours late