How they describe hurricanes makes me feel like it isnt a story event and is an actual event that happens in the open world.
This is what it says on the Game Informer article about hurricanes: Although Shepherd doesn't share how often these major storms occur and how gameplay or the story will be impacted, he paints a picture of how they will be depicted, saying that "heavy clouds, strong winds, dense atmospherics, and a lot of rain combine so that everything is dripping wet, water is gushing off roof edges and lampposts, thunder rumbles and flashes of lightning light up the clouds dramatically." From this piece of information it leads me to believe that it isn't a story event just based of the description