The U.S. Coast Guard has evacuated four workers from a remote wildlife refuge in the path of a powerful hurricane in the Pacific.

A Coast Guard plane from Hawaii picked up the Fish and Wildlife Service workers on Monday from Johnston Atoll, which is about 825 miles (1,300 kilometers) southwest of Honolulu.

Hurricane Walaka was crossing the island and heading north on Tuesday with maximum sustained winds near 150 mph (240 kph). Derek Wroe, a meteorologist at the Central Pacific Hurricane Center, said Johnston would feel the storms effects through the night.

Strong winds may damage trees and structures. Because the island is low-lying, large waves crashing ashore could also inflict damage.

Johnston Atoll is about 50 square miles (130 square kilometers) and consists of four small islands. The four workers are members of a field biology crew.

The National Weather Service forecast the storm would pass over parts of the Papahanaumokuakea Marine National Monument on Wednesday, but it wasn't expected to threaten Hawaii's most populated islands.

An American ship captain accidentally discovered Johnston when his ship ran aground in 1796. The U.S. government designated the island a bird refuge in 1926. President Franklin Roosevelt placed it under Navy control in 1934.

Underwater volcanic eruptions formed the island, which has eroded and subsided over millions of years.