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On May 20, 2020, Super Cyclone Amphan struck West Bengal, India, close to the Bangladeshi border. This event marked the most intense storm ever documented in the Bay of Bengal. MercuryNewsWhile cyclones and hurricanes might appear to be distinct natural phenomena, they share many similarities. Both are classified as tropical cyclones, defined by the World Meteorological Organization (WMO) as "a rapidly rotating storm system that forms over tropical oceans, deriving its energy from warm waters." The distinction between cyclone vs. hurricane primarily hinges on their geographical location.
What Are Tropical Cyclones?
A tropical cyclone — referred to as a hurricane, typhoon, or cyclone depending on the region — is a highly organized and potent weather system that forms over warm equatorial ocean waters (typically within 300 miles of the equator). It is characterized by low atmospheric pressure, persistent high winds, heavy rainfall, and severe thunderstorms. The intensity of a cyclone can increase significantly due to warm ocean waters.
Tropical cyclones develop globally at various times of the year, including regions such as the Northwest Pacific Ocean, the North Indian basin, the North Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea.
Cyclone vs. Hurricane
The primary distinction lies in the terminology used to classify these storms based on their geographic locations:
- A tropical cyclone with wind speeds of at least 74 miles per hour (119 kilometers per hour) occurring in the Caribbean, the Gulf of Mexico, the North Atlantic Ocean, or the central North Pacific Ocean is termed a hurricane. Examples include Hurricane Katrina and Hurricane Harvey.
- Storms in the Northern Indian Ocean (the Bay of Bengal and Arabian Sea) are classified as tropical cyclones.
- In the western South Pacific and southeast Indian Ocean, these systems are known as severe tropical cyclones.
- In the North Pacific, they are called typhoons.
Why Tropical Cyclones, Hurricanes and Typhoons Have Different Names
If these storms all feature strong winds and heavy rainfall, why are they named differently? The primary reason is that hurricanes, cyclones, and typhoons form in distinct geographic regions and during varying seasons. The tropical cyclone season in the Northern Indian Ocean, encompassing the Bay of Bengal and Arabian Sea, experiences two active periods: one from April to June and another from September to December, with the most intense cyclones occurring during the latter.
In contrast, the Atlantic hurricane season spans from June 1 to November 30. The most powerful and destructive hurricanes typically emerge in August, September, and early October due to several factors: African easterly waves are most pronounced, wind shear—which can disrupt storm formation—is minimal, ocean temperatures are at their highest, and atmospheric instability increases during this period.
In the North Pacific, typhoons predominantly form between May and October, though they can occur year-round.
The Bay of Bengal is the most dangerous region for these storms, hosting 26 of the 35 deadliest tropical cyclones in history. In May 2020, Super Cyclone Amphan struck eastern India, becoming the strongest storm ever recorded in the Bay of Bengal.
Intense Storm Surge
The Bay of Bengal, the largest bay globally, borders India, Bangladesh, Myanmar, and Indonesia. Its shallow, concave shape makes it highly susceptible to cyclones, as these features help funnel storms as they develop, according to BBC. Combined with high sea surface temperatures, these conditions create an environment ripe for extreme cyclones.
Hurricanes in the Atlantic are also growing stronger, and climate change is likely a contributing factor, as highlighted in a June 2020 study published in Proceedings of the National Academy of Sciences.
By analyzing 39 years of data, researchers found that storms are not only intensifying but also becoming more frequent. While this trend could align with other factors, Live Science notes that both climate models and real-world observations strongly suggest climate change is the primary driver.
Hurricane John holds the record as the longest-lasting and farthest-traveling tropical cyclone. It lasted from August 11 to September 13, 1994, covering 8,188 miles (13,177 kilometers), and even crossed the international date line, transforming into Typhoon John.
