WHAT IS A HURRICANE?
A hurricane is a type of storm called a tropical cyclone, which forms over tropical or subtropical waters.
A tropical cyclone is a rotating low pressure weather system that has organised thunderstorms but no fronts (a boundary separating two air masses of different densities).
Tropical cyclones with maximum sustained surface winds of less than 39 miles per hour are called tropical depressions.
Those with maximum sustained winds of 39 mph or higher are called tropical storms.
When a storm’s maximum sustained winds reach 74 mph, it is called a hurricane.
The Saffir-Simpson hurricane wind scale is a 1 to 5 rating, or category, based on a hurricane’s maximum sustained winds. The higher the category, the greater the hurricane’s potential for property damage.
Hurricanes originate in the Atlantic basin, which includes the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico, the eastern North Pacific Ocean and, less frequently, the central North Pacific Ocean.
A six-year rotating list of names, updated and maintained by the World Meteorological Organization, is used to identify these storms.
Hurricane season begins on 1 June and ends 30 Nov. although hurricanes can, and have, occurred outside of this time frame.
Source: National Oceanic and Atmospheric Administration.
HURRICANE TERMS:
TROPICAL CYCLONE
An organised low-pressure weather system of clouds and thunderstorms that develops in the tropics.
TROPICAL WAVE
A kink or bend in the normally straight flow of surface air in the tropics which forms a low-pressure trough, or pressure boundary, showers and thunderstorms. Can develop into a tropical cyclone.
TROPICAL DEPRESSION
A tropical cyclone with maximum sustained winds near the surface of less than 39 mph.
TROPICAL STORM
A tropical cyclone with winds of 39 to 73 mph.
HURRICANE
A tropical cyclone with winds of 74 mph or greater.
EYE
The low-pressure centre of a tropical cyclone. Winds are normally calm and sometimes the sky clears. This lull often signifies the storm’s eye – not its end. Anyone riding out a hurricane should wait for authorities to announce that the danger has passed.
EYE WALL
The ring of thunderstorms that surrounds a storm’s eye. The heaviest rain, strongest winds and worst turbulence are normally in the eye wall.
STORM SURGE
Storm surge is a dome of water that is pushed ashore by the oncoming hurricane’s winds. Storm surge and large battering waves can endanger lives, destroy buildings, erode beaches and damage roads. This flooding accounts for the largest number of hurricane fatalities.
This article originally appeared in Compass Media’s 2026 Emergency Guide.
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