After strengthening into a Category 4 storm Wednesday, Hurricane Fiona was forecast to hit Bermuda later this week, bringing threats of hurricane-force winds and surf swells as the storm continues to intensify. 

Bermuda is likely to avoid the worst of the storm’s wrath suffered by Puerto Rico, but residents face the possibility of hurricane and tropical storm conditions late Thursday into early Friday, according to the National Hurricane Center.

The forecast also includes a storm surge on the island, including elevated water levels and “large and destructive waves” near the coast, according to the NHC. The Bermudan government advised residents to prepare for the storm by checking water, medicine and food supplies and securing boats and homes.

The storm flooded Puerto Rico with 6 to more than 25 inches of rain in some areas earlier this week, with parts of the island without electricity or running water and under the threat of additional flooding and mudslides days later. Puerto Rico’s fragile electrical grid and continual recovery from Hurricane Maria in 2017 has compounded challenges for rescue and rebuilding efforts.

At least four people have died through the Caribbean, officials said.