(CNN) - Hurricane Humberto's core has passed its closest point of approach to Bermuda, but its strong hurricane-force winds will continue whipping the island well into Thursday morning.
More than 27,900 customers -- 80% of the territory -- were left in the dark in the wake of the storm, a representative of the power utility company Belco told CNN.
The company was in an "emergency state" as rain and strong winds continued to lash the island, the company's website said.
Late Wednesday night, the Category 3 storm was packing sustained winds of 120 mph. The storm's strong winds extended 80 miles outward from its center as it churned about 75 miles north of Bermuda.
Southern coastal parts of the island are under flood threat through Thursday from the storm surge and dangerous breaking waves," the hurricane center said.
A buoy measured a wave of more than 30 feet Wednesday, it said.
Heavy rainfall Thursday
Humberto could dump up to 6 inches of rain by Thursday in some spots, forecasters said.
Large swells will also continue to increase into tomorrow, the hurricane center said.
"Swells will continue to affect the northwestern Bahamas and the southeastern coast of the United States from east-central Florida to North Carolina during the next couple of days," the center said.
The swells could cause life-threatening and rip current conditions, it said.
Bermuda Premier David Burt said Wednesday he had been advised conditions would begin to improve as the hurricane moved further away.
It's one of three storms
Humberto is one of three storms drawing attention in the Atlantic basin. Imelda, a tropical depression, has rescue teams on alert as it threatens to dump the most rain since Hurricane Harvey on eastern Texas. And Tropical Storm Jerry, still far east of the Leeward Islands, could strengthen into a hurricane by week's end.
Hurricanes don't often approach Bermuda
Humberto i s the second major Atlantic hurricane. The Atlantic Ocean paradise rarely sees a storm this big and powerful.
Only 21 hurricanes have passed within 100 miles of Bermuda over the past century, with Hurricane Gonzalo in 2014 the last to make landfall there.
"They go by, but it's such a small target," CNN meteorologist Monica Garrett said. "So, they don't usually make landfall."
CNN's Steve Almasy contributed to this report.
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