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 Category 1 hurricane with sustained winds of 85 mph on Friday evening and is more than 300 miles east of the northeastern Caribbean’s Leeward Islands, according to the Nation...

Even without a direct hit, both areas may experience rough surf and dangerous rip currents.