Tropical Storm Fiona headed for Puerto Rico on Saturday night, with forecasters warning it likely would grow into a hurricane before hitting on Sunday with extremely heavy rains with the potential to cause landslides, severe flooding, and power outages.

The storm already lashed several eastern Caribbean islands, with one death reported in the French territory of Guadeloupe. More than 20 other people were rescued amid heavy wind and rain that left 13,000 customers without power, with the storm tearing up roads, downing trees and destroying at least one bridge.

Fiona was centered 150 miles (240 kilometers) southeast of Ponce, Puerto Rico, late Saturday and had maximum sustained winds of 60 mph (95 kph). It was moving west-northwest at 8 mph (13 kph) on a path forecast to pass near or over Puerto Rico on Sunday. Fiona was expected to become a hurricane before reaching Puerto Rico’s southern coast.