Tropical cyclone
A tropical cyclone is a rapidly rotating low-pressure storm system that forms over warm tropical or subtropical ocean waters and is powered by heat and moisture from the sea.
A tropical cyclone is a rapidly rotating low-pressure storm system that forms over warm tropical or subtropical waters and is powered by heat and moisture from the sea. It is the generic term for storms known regionally as hurricanes, typhoons, or cyclones.
What it is
A tropical cyclone is a warm-core, non-frontal low-pressure storm with a closed surface wind circulation around a well-defined centre. Its key features include an eye (a calm centre), an eyewall of the strongest winds and rain, and spiral rainbands. It is classified as a tropical cyclone once winds reach at least 34 knots (63 km/h) in some regional definitions.
Why it matters
Tropical cyclones are among the most dangerous natural hazards, producing destructive winds, heavy rain, storm surge, coastal flooding, and secondary hazards like tornadoes and lightning. In Canada, their remnants can bring heavy rain, strong winds, and flooding, mainly affecting Atlantic Canada and, more rarely, other regions.
Key details
The same storm type has different regional names: hurricane (Atlantic and eastern North Pacific), typhoon (western North Pacific), and cyclone (Indian Ocean and South Pacific). Tropical cyclones are named once they reach a specified intensity in many forecasting systems. They form over warm ocean waters, typically above about 26.5 °C, when atmospheric conditions are favourable.
In short
- A tropical cyclone is a warm-core, non-frontal storm that forms over warm ocean waters.
- It is called a hurricane, typhoon, or cyclone depending on the region.
- Key features include an eye, eyewall, and spiral rainbands.
- Main hazards: strong winds, heavy rain, storm surge, and flooding.
Tropical cyclones mainly affect Canada indirectly, but their remnants can contribute to heavy rain, strong winds, storm surge, and flooding in Atlantic Canada and, more rarely, other regions.
Quick questions
What is a tropical cyclone?
Are hurricanes and typhoons tropical cyclones?
What hazards do tropical cyclones bring?
Sources
- National Weather Service — https://www.weather.gov/mob/tropical_definitionsSupports: Definition of tropical cyclone as a warm-core, non-frontal synoptic-scale cyclone over tropical or subtropical waters.
- World Meteorological Organization — https://www.wmo.int/topics/tropical-cycloneSupports: Regional naming, general description, and hazards of tropical cyclones.
- Bureau of Meteorology — https://www.bom.gov.au/resources/learn-and-explore/tropical-cyclone-knowledge-centre/what-is-a-tropical-cycloneSupports: Formation over warm waters, sea-surface temperature threshold, and Australian regional definition.
- Met Office — https://www.metoffice.gov.uk/research/weather/tropical-cyclones/factsSupports: Generic term usage, regional names, and intensity thresholds for tropical depressions, storms, hurricanes, and typhoons.
- National Weather Service — https://www.weather.gov/media/lwx/skywarn/Tropical%20Cyclones.pdfSupports: Basic structure and regional naming conventions.
- NASA Earthdata — https://www.earthdata.nasa.gov/topics/human-dimensions/tropical-cyclonesSupports: WMO-based definition and low-pressure eye-centered structure.