red flag warnings

For the last week or so there has been a red flag flying over the old fort but this weekend an older style US flag has been flying there. I'm taking this as a good sign. Did we win over some unknown foe?  There have also been a lot of cannon and gun shots. I understand from the local news that the reenactment this weekend covered life over several ages of history which may explain the various kinds of gunfire I was hearing but it didn't answer my question about the red flag.  I googled red flag and learned that a red flag can be a sign of a social revolution but more often it's a warning of danger.  It can mean that weather conditions are ideal for forest or grass fires.  I don't think that can be it around here this month. I'm thinking it was a warning that the music festival was coming.