SAN JUAN, Puerto Rico — Hurricane Ernesto charged toward Bermuda on Friday as officials on the tiny island in the middle of the Atlantic Ocean prepared to open shelters and close government offices. The Category 2 storm was located 255 miles (415 kilometers) south-southwest of Bermuda. It had maximum sustained winds of 100 mph (160 kph) and was moving north-northeast at 13 mph (20 kph).

Ernesto was expected to strengthen further on Friday before it passes near or over Bermuda on Saturday. Tropical storm conditions including strong winds and life-threatening floods were expected to start affecting Bermuda on Friday afternoon, according to the National Hurricane Center. “Preparations to protect life and property should be rushed to completion,” the center said.

The storm was forecast to dump between 6 and 12 inches of rain, with up to 15 inches in isolated areas. Forecasters noted that Ernesto was a large hurricane, with hurricane-force winds extending up to 70 miles (110 kilometers) from the center and tropical-storm-force winds extending up to 265 miles (425 kilometers). In preparation for the storm, officials in the wealthy British territory announced they would suspend public transportation and close the airport by Friday night.

National Security Minister Michael Weeks had urged people to complete their hurricane preparations by Thursday. “Time is running out,” he said. Bermuda is an archipelago of 181 very tiny islands whose land mass makes up roughly half the si.