A couple of years ago I was scheduled to fly from BWI to someplace on NW early one Saturday morning. The radio report said that BWI airport was closed due to freezing rain. I attempted to call NW and got only a busy signal. Their website claimed that all of their flights were operating normally at BWI.
Since an emergency had been declared and some major roads had been closed by the state police, I went back to sleep. I simply did not make the trip.
Eventually I was allowed to use the fare paid as a credit toward another trip on NW.