Tropical seas breed the most powerful storms. A hurricane is a severe tropical cyclone with sustained winds of 64 knots or more, forming over warm ocean waters and bringing extreme wind, rain, and storm surge.

In the Atlantic and Northeast Pacific the term hurricane is used; the same storms are called typhoons or cyclones elsewhere. Ships avoid the core of a hurricane by wide margins, using forecasts and the known structure of the storm—dangerous semicircle, navigable semicircle, and eye—to plan escape routes.

Even well-found ships can be overwhelmed if caught near the center. Heavy weather preparations, reduced speed, and altered course are standard responses. Port closures and convoy delays ripple through schedules when a hurricane threatens a coastal region.

• Intense tropical cyclone with winds of 64 knots or more
• Forms over warm ocean water
• Avoided by ships through routing and timing
• Brings extreme wind, seas, and coastal surge