The banner suggests checking the @StackStatus Twitter account, or the status blog. However the latter hasn't been updated in over a year:
Not only is today's outage not mentioned, but neither is any of of the planned maintenance in the last year. Since the blog appears to be abandoned it should be removed from the banner because it's no longer a current source of information.
wwwin the URL. With this question now overcome by events I'm not sure what should be done with it.