Decisions on part-time evening classes are usually made by 1 p.m. During major storms, the line is updated frequently with new information on library hours, shuttle service, etc. You don't have to wait for radio announcers to get through a long list of other institutions. Completeness and accuracy. In a weather emergency, a big university like Hopkins has a lot of information to convey to students, faculty and staff all over the Baltimore-Washington area.
Broadcasters have time to mention only the bare essentials, and they sometimes get even that wrong.