Crowds thinned Tuesday on the beaches of North Carolina’s Outer Banks ahead of a tropical weather system that threatened to bring strong winds and heavy rains that could flood low-lying areas.

Elsewhere, a powerful hurricane threatened to pass “dangerously close” to Hawaii, and a hurricane watch was issued for parts of Florida stretching from northwest of Tampa to east of Panama City.

On North Carolina’s Hatteras Island, a slow stream of dozens of cars from places including Maryland, New York and Ohio headed north toward a bridge to the mainland — but other vacationers stayed and some surfers dove in for taller waves. Several Outer Banks businesses reported cancellations and slower foot traffic.

Residents of Hawaii’s Big Island were evacuating animals and stockpiling water Tuesday, bracing for what could be the first hurricane to make landfall in the state in decades.

The National Weather Service issued a hurricane warning as the major Category 3 storm dubbed Madeline hurtled west toward the island, urging residents to rush through preparations to protect themselves and their property and expect hurricane conditions within the next 36 hours.

“Hopefully our roofs stay on, and our houses don’t float way or get blown away,” said Big Island resident Mitzi Bettencourt, who boarded up walls of glass windows at her brother’s oceanfront home. “It’s like, ‘Oh my God, are we going to get flattened or what?’?’’