I read about halfway down and then skipped to the end, so ~ sorry if I'm repeating anything already noted:

It's not the amount of snow that determines whether a locality shuts down: it's how much more snow falls than usual, than people are prepared for. We get an inch or two every 15-20 years in New Orleans. There are no snowplows here, of course, and most people have absolutely no experience driving on any kind of frozen surface. So, when we have a snow day like we did last month, the whole town shuts down (for ONE day).

Washington DC is somewhat further north and gets a bit more snow than we do, but they are almost as helpless as we are when there is more snow than minor flurries, and when the stuff "sticks" and actually stays on the ground for more than a predawn hour or two.

The Obama family recently moved there from Chicago, where they are VERY accustomed to, and well-equipped for, major snowstorms. On about his third or fourth day in office, the President told the press corps that his daughters had to stay home from school and couldn't understand why such a piddling amount of snow caused their school to shut down.

Incidentally, the DC public schools stayed open. It was only the suburban private schools, like Sidwell Friends, that closed.