I was in 6th grade. It was a shitty day all around -- there was a metrorail accident under the river. I was on a school bus for 4 hours while getting home in the snow. The plane hit a bridge and went into the river.
Think of what you know about DC traffic when there's a flake of snow in the air, and put an airliner crash and a metro accident on top of that.
Maybe it's not logical, but I'm still not a fan of flying through National in the winter.