GEORGE TOWN, Cayman Islands — Frantic vacationers lined up at ticket counters and slept on the airport floor, rushing to leave the Cayman Islands ahead of an expected brush today from Hurricane Dean, which has left a deadly trail of destruction across the Caribbean.

With winds nearing 150 mph, Dean was expected to pass to the south of the Caymans but the government said it still posed a “significant threat” to the islands and imposed a curfew on the British territory. Forecasters said the islands could receive up to 12 inches of rain.

Cayman Islands Gov. Stuart Jack said all but 1,500 tourists had been evacuated from the British territory by Sunday afternoon.

“It’s kind of spooky,” said George Mitchell of Detroit, who missed his flight out. “We don’t know what to do or where to go. It freaks you out.”

The National Hurricane Center in Miami said the first hurricane of the Atlantic season was a powerful Category 4 storm, and could reach the highest level — Category 5, with maximum winds greater than 155 mph — later today.

As of 8 a.m. today, Dean was about 440 miles east of Belize City, traveling west at about 21 mph, the National Hurricane Center said.

In Texas, already saturated after a rainy summer, emergency operations centers opened, prison inmates were moved inland, and officials distributed sandbags even though Dean’s path was still uncertain.