Virgin Islands ? Omar strengthened into a fierce Category 3 hurricane late Wednesday as it pummeled St. Croix with heavy rains and winds, sinking boats in the harbor, knocking down trees and forcing workers to shut down a major oil refinery.

The fast-growing hurricane was roaring toward the U.S. and British Virgin Islands with top winds of 115 mph. Omar’s center appeared set to edge passed the tiny tourist islands, but forecasters warned they could still get hit.

“It could thread the needle, but any kind of track deviation and any of those islands will be clobbered,” said Jack Beven of the U.S. National Hurricane Center.