Tropical cyclone

Meteorological phenomenon

A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rains. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, and cyclone.

Formation

Formation of a tropical cyclone

Tropical cyclones form over warm ocean waters near the equator. The primary energy source for these storms is the release of the heat of condensation from water vapor condensing at high altitudes. This process requires a sea surface temperature of at least 26.5 °C (79.7 °F) and a pre-existing weather disturbance, low vertical wind shear, and sufficient distance from the equator to provide Coriolis force to develop a cyclonic circulation.

Structure

Eye of Hurricane Florence

A tropical cyclone's structure is characterized by a central "eye," a region of mostly calm weather at the center of the storm. The eye is surrounded by the "eyewall," where the most severe weather occurs, including the strongest winds and heaviest rains. The storm's outer rainbands, which spiral inward toward the center, can extend hundreds of kilometers from the eye.

Classification

Tropical cyclones are classified by their maximum sustained winds. In the Atlantic and Northeast Pacific, a tropical cyclone with maximum sustained winds of 74 mph (119 km/h) or higher is called a hurricane. In the Northwest Pacific, it is called a typhoon. In the South Pacific and Indian Ocean, it is simply referred to as a cyclone.

Impact

Hurricane diameters in the US Gulf Coast

Tropical cyclones can cause extensive damage and loss of life due to their high winds, heavy rains, and storm surges. The storm surge, a rise in sea level caused by the storm's winds, can lead to severe coastal flooding. Inland flooding from heavy rains can also cause significant damage far from the coast.

Climate Change and Tropical Cyclones

Climate change impact on hurricane wind speeds

There is growing evidence that climate change is affecting tropical cyclones. Warmer ocean temperatures can increase the intensity of these storms, leading to more powerful hurricanes and typhoons. Additionally, rising sea levels can exacerbate the impact of storm surges.

Notable Tropical Cyclones

Hurricane Paulette

Some of the most notable tropical cyclones in history include Hurricane Katrina, which devastated the Gulf Coast of the United States in 2005, and Typhoon Haiyan, which struck the Philippines in 2013. These storms are remembered for their catastrophic impacts and the lessons learned in their aftermath.

Related Pages

• Hurricane preparedness
• List of tropical cyclone records
• Tropical cyclone naming