NAGS HEAD, N.C. — The plywood boards nailed over the windows of oceanfront houses rattled in the wind. Fields of cattails and beach grass bowed. Little girls on the beach leaned against the gales, and hulking pickup trucks wobbled on the rain-slicked roads.

Hurricane Florence announced its looming arrival on Thursday with a blustery, stomach-twisting shriek. While the storm with its torrential rains and storm surge lurked offshore, the 50-mile-per-hour winds that lashed the Outer Banks gave these emptied-out islands and other coastal cities across the Carolinas a preview of its power.

“It rocks the house,” said Traci Stafford, one of a couple of hundred people who decided to stick it out on Ocracoke Island, now entirely severed from the mainland. Ms. Stafford had abandoned her trailer to weather the storm at a friend’s bed-and-breakfast.

As the sky turned the color of steel wool and more and more cars headed toward the mainland, these summertime vacation islands turned into ghost towns populated mostly by wind and rain. Power lines vibrated like guitar strings. Snowballs of sea foam sailed over dunes and splattered in the streets. Bushes bent and twirled like modern dancers.