Erin is the fifth named storm to develop during the Atlantic hurricane season, which started just over two months ago. Last week, Tropical Storm Dexter formed in the western Atlantic but didn't pose a threat to land. In early July, Tropical Storm Chantal made landfall on the Carolina coast, bringing deadly flooding to the region.

Powerful Hurricane Erin has undergone a period of astonishingly rapid intensification — a phenomenon that has become far more common in recent years as the planet warms. It was a rare Category 5 for a time Saturday before becoming a Category 4,