Employees are on "code green," meaning essential personnel should report for work; no second-shift custodians are on duty; and all evening and daycare activities are canceled.
The school system advised essential personnel to wait for instructions on reporting times.
Harford County government offices are opening on time, and liberal leave is in effect.
More than 6,400 BGE customers were without power in Harford County as of 5:30 a.m. Thursday.
Patterson Mill High School was one of three locations where the county set up a shelter for citizens without power.