Absolutely a tornado
At first, it's well above ground but then it touches down. It intensifies and then begins dissipating. Tornadoes can move fast or they can move slowly at first, can change directions. They're volatile twisters and I'm thankful I've never been hit by one. Living the Midwest all of my life except for 3 years in England, I've been in a helluva lot of tornado warnings when they were all around.
I can't believe no one could tell them what it was. Maybe they don't usually get tornadoes up there but still... I've never been near a hurricane but I know what it is!