Also, many bus turnaround sites and bus stops are not yet clear, she said.
In December, schools were closed twice for snow and twice for ice, she said.
Schools closed once in January and once in February for snow before this week's storm hit, which tentatively pushed the last day of school up against the predetermined graduation date of June 13.
"When we moved into June 13, we moved into uncharted waters," she said.
Now school officials will have to determine how the additional four days will be spread out across the already taut calendar.
Mowen said they will have to determine how and if students can attend classes while graduation ceremonies are taking place June 13.
Unlike West Virginia, whose state law says students cannot go to school past June 9 this year, Maryland won't allow students to go to school beyond June 30, but Mowen said it's highly unlikely school will be in session that far into the summer.
She said the school system has eight schools lacking air-conditioned space, which will factor into its decision to keep students in classes into summer.
Keeping students in classes later in the school day might be a possibility, she said. Also, already scheduled days off like spring break - April 18 and 21 - or Memorial Day, May 26, might be considered as make-up days, she said.
"Some of those days are part of staff-negotiated agreements," she said.
School administrators and teachers will likely deliberate all avenues concerning make-up time and Schools Superintendent Elizabeth Morgan will probably talk to other state district superintendents to discuss how other school systems are handling the weather, she said.
Mowen said the Washington County Board of Education will probably vote on any proposed changes in mid- to late March.
"It's not a decision we plan to make quickly," she said.