Like giant lawnmowers, more than a dozen twisters hit Texas, Oklahoma and Kansas, including two at once.
Witnesses posted images on social media showing the swirl near the Marina Bay Sands hotel.
The storm swept over Mildura in Australia with wind gusts reaching up to 87km/h (54mph).
Extremely severe cyclonic storm Fani is due to make landfall during Friday morning, local time, bringing heavy rain, strong winds and a powerful storm surge.
Parts of Mozambique had over 300mm of rainfall since Kenneth made landfall last Thursday