RODANTHE, N.C. — 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’s Gulf Coast because of a tropical depression in the Gulf of Mexico.

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.

Some beaches were all but empty during a morning of gray skies and misty rain.

The weather system off the coast was expected to strengthen and pass near the Outer Banks, bringing sustained winds as high as 45 miles per hour and heavy rains of up to 5 inches in some areas.

Associated Press