Hurricane Erin exploded in strength to a Category 5 storm in the Caribbean on Saturday, rapidly powering up from a tropical storm in a single day, the National Hurricane Center said.

Erin strengthened into a powerful Category 4 hurricane in the Caribbean on Saturday and continues to intensify, the National Hurricane Center said.

The storm is expected to remain over open waters, although tropical storm watches were issued for Anguilla and Barbuda, St. Martin and St. Barts, Saba and St. Eustatius and St. Maarten.