m
What exactly are people doing in the bathroom that makes it a "Severe Weather Area"??? Perhaps some Pepto Bismol or Immodium would help with that?
In all seriousness, Ben suggested that it was a place that people were supposed to safely gather in the event of extreme weather. While this explanation definitely seems plausible, I prefer my explanation of Texans eating too much BBQ and beans, and passing enough gas to create a tornado.