Charleston: Hurricane Dorian is back to a Category 3 storm and has begun raking the south-east US coast, threatening to inundate low-lying coasts from Georgia to south-west Virginia with a dangerous storm surge after its deadly mauling of the Bahamas.

Dorian crashed into the island nation earlier in the week as its strongest hurricane on record leaving widespread devastation and at least 20 people dead. But it weakened substantially in the days since, dropping from a Category 5 to a Category 2 storm before increasing again late on Wednesday US time (Thursday afternoon AEST).

Jasmine Farrinton hugs Roshane Eyma after she was rescued and flown to Nassau after Dorian devastated the Abaco Island, Bahamas. Credit:Getty Images

Dorian could maintain this intensity for about 12 hours or so, but guidance is showing shear increasing, and that should result in gradual weakening in the next two days, according to the National Hurricane Centre.