Where I grew up, schools closed on a school by school basis.
Listening to the tv/radio for snow closings was something that took a long time, but it was quite a build up when you FINALLY heard that your school was closed.
The schools in the DC area are set up so it's all or nothing for a whole county.
I can't tell you how many times Loudoun county would close because the western end of the county had a bit of snow or ice, but the rest of the county from Leesburg to the Fairfax county line was just fine.
It's just extremely inefficient.
In the mean time, if you can't find a relative who can watch the kids, try finding a drop in day care (Kindercare or something like that) where they can take your kids for a day.
It's not ideal, but some parents (if the kids are older) will drop them off at a library for a day (or leave them home alone) and it's SUCH a dangerous practice I don't know what they could be thinking.
I've heard such horrible stories about this I'm surprised the librarians don't call CPS for child abandonment more often.