Schools in Baltimore City and Anne Arundel, Baltimore, Carroll, Harford and Howard counties canceled classes Tuesday, as did most counties around the state, from Prince George's to Worcester to Frederick.
Forecasters are expecting significant snowfall for the Baltimore area tonight into Wednesday, with some predicting up to 20 inches.
Most school systems have already used the five snow days generally built into their calendars, leaving school officials to contend with the possibility of keeping students and teachers in the classroom well into the summer.
"The first thing we consider is the safety of students," said Carey Geddis, a spokeswoman for Carroll County schools. "If we need to be off for weather, we'll be off. It's never, we're not going to take off because of makeup days."
One school system had contemplated looking to scheduled holidays to make up a day. Frederick County schools considered eliminating Monday, Presidents Day, as a holiday and requiring student attendance in order to make up a snow day, but decided against it, saying it was "short notice" for parents and guardians.
Other school system officials said they had not considered opening schools on Presidents Day and would simply add the makeup days to the end of the school year.
Anne Arundel has already exceeded the four snow days in its calendar and has requested a waiver from the state for two of those days. Any additional days will be added to the end of the school year, said Bob Mosier, a spokesman for the school system.
The state Department of Education has rarely granted waivers in the past.
Howard County had already scheduled early dismissals and a day off this week: Wednesday and Thursday are half-days, and students are off Friday for parent-teacher conferences.
Baltimore County, which announced Monday that schools would close both today and Wednesday because of the incoming storm, will have two snow days remaining if it reopens Thursday, said Phyllis Reese, a spokeswoman for the system.
"At this point, we're in good shape," Reese said.