A rare double hurricane could hit the US, potentially bringing flash flooding and violent winds to the east coast.

Hurricane Humberto is rapidly strengthening over the central Atlantic and could become a major hurricane on Friday or Saturday.

Humberto is not currently expected to make landfall in the US, however meteorologists fear that another tropical storm, likely to be named Hurricane Imelda, has the potential to join Humberto in the region and hit the Southeast US with little warning.

The two systems in the Atlantic could collide to form a “superstorm” that may hit the Carolinas, although the phenomenon is notoriously difficult to forecast.