The first major hurricane threatening a direct hit on the United States in more than 10 years lashed Florida on Friday with heavy rains and winds after killing at least 339 people in Haiti on its destructive march north through the Caribbean.

Hurricane Matthew packed gusts of 100 miles per hour (160 kph) as it tracked north-northwest along Florida’s east coast, the National Hurricane Center said in an advisory. The storm’s eye was 25 miles (40 km) east of Cape Canaveral, home to the nation’s chief space launch site.

“We are seriously ground zero here in Cape Canaveral — hunkered down, lights flickering, winds are crazy,” said resident Sandy Wilk on Twitter.

The storm downed power lines and trees and destroyed billboards in Cape Canaveral, reported Jeff Piotrowski, a 40-year-old storm chaser from Tulsa, Oklahoma.

“The winds are ferocious right now,” he said. “It’s fierce.”

NASA and the U.S. Air Force, which operate the Cape Canaveral launch site, took steps to safeguard personnel and equipment. A team of 116 employees was bunkered down inside Kennedy Space Center’s Launch Control Center to ride out the hurricane.

“We’ve had some close calls, but as far as I know it’s the first time we’ve had the threat of a direct hit,” NASA spokesman George Diller said by email from the hurricane bunker.

No significant damage or injuries were reported in West Palm Beach and other communities in south Florida where the storm downed trees and power lines earlier in the night, CNN and local media reported.

About 300,000 Florida households were without power, local media reported. In West Palm Beach, street lights and houses went dark and Interstate 95 was empty as the storm rolled through the community of 100,000 people.

Hurricane Matthew was carrying extremely dangerous winds of 120 mph (195 kph) on Friday, but is expected to gradually weaken during the next 48 hours, the hurricane center said.

Matthew’s winds had dropped on Thursday night and into Friday morning, downgrading it to a Category 3 on the five-step Saffir-Simpson scale of hurricane intensity. It could either plow inland or tear along the Atlantic coast through Friday night, the Miami-based center said.

A dangerous storm surge was expected to reach up to 11 feet (3.35 meters) along the Florida coast, Ed Rappaport, deputy director of the Miami-based NHC, said on CNN.

“What we know is that most of the lives lost in hurricanes is due to storm surge,” he said.

Some 339 people were killed in Haiti, local officials said, and thousands were displaced after the storm flattened homes, uprooted trees and inundated neighborhoods earlier in the week. Four people were killed in the Dominican Republic, which neighbors Haiti.

Damage and potential casualties in the Bahamas were still unclear as the storm passed near the capital, Nassau, on Thursday and then out over the western end of Grand Bahama Island.