A hurricane is a tropical cyclone with sustained winds of 119 km/h or more (Category 1 on the Saffir-Simpson scale). The same phenomenon is called a typhoon in the western Pacific and a cyclone in the Indian Ocean. Hurricanes are the most powerful weather systems on Earth, releasing energy equivalent to 200 times global electricity production every day through latent heat of condensation.
Formation requires specific conditions: sea surface temperatures above 26.5 °C over a depth of at least 50 m, sufficient Coriolis effect (at least 5° from the equator), low wind shear between lower and upper troposphere, and a pre-existing atmospheric disturbance (e.g., tropical wave, monsoon trough). The warm ocean provides the energy through evaporation; as the vapour condenses in towering cumulonimbus bands, it releases latent heat that powers the rising motion and surface pressure drop.
A mature hurricane features a calm eye (20–60 km diameter, cloud-free, sinking air), surrounded by the eyewall (the most destructive zone, with the strongest winds and heaviest rain), and spiral rainbands extending hundreds of kilometres outward. Hurricane hazards include extreme wind, storm surge (the deadliest threat — sea level rises of 3–9 m), torrential rainfall and flooding, and embedded tornadoes. The eastern Atlantic hurricane season runs June–November, with the peak in September. Satellite imagery enables tracking from formation to landfall, but intensity forecasting remains challenging.