Typhoon, Hurricane, Cyclone: What's the Difference?

A massive cyclone that slammed into India's east coast on Saturday has left more than a dozen dead and forced more than a half a million people to flee homes that lie in vulnerable coastal and low-lying areas.

"This is one of the largest evacuations undertaken in India," M. Shashidhar Reddy, vice chairman of the National Disaster Management Authority, told reporters in the capital, New Delhi. "Our priority is to minimize loss of life."

Cyclone Phailin (a Thai word for "sapphire") is officially the strongest storm to batter India since Cyclone Odisha made landfall in the same region in 1999 and killed 10,000 people. At the peak of Phailin's power, its winds reached speeds of up to 257 kilometers per hour. By Sunday, Phailin's fierce winds had diminished to 129 kilometers per hour, and the cyclone's strength continues to lessen as it moves farther inland.





In the northern Indian Ocean, they're called "severe cyclonic storms." In the southwestern Indian Ocean, they're just "tropical cyclones."

To be classified as a hurricane, typhoon, or cyclone, a storm must reach wind speeds of at least 119 kilometers per hour.

If a hurricane's winds reach speeds of 179 kilometers per hour, it is upgraded to an "intense hurricane."

If a typhoon hits 241 kilometers per hour—as Usagi did—then it becomes a "supertyphoon."

Different Seasons



Whatever you choose call them, these monster storms are powerful natural events with the capacity to wreak some serious havoc.

According to NOAA's National Hurricane Center, the average hurricane eye—the still center where pressure is lowest and air temperature is highest—stretches 48 kilometers across, with some growing as large as 200 kilometers wide.

The strongest storms, equivalent to Category 5 on the Saffir-Simpson scale, have sustained winds that exceed 250 kilometers per hour.

With the aid of satellites and computer models, such storms can be predicted several days in advance and are relatively easy to track. But as Hurricane Sandy showed recently, predicting the path that a hurricane or typhoon or cyclone will take after it's formed is still tricky.

Effects of Global Warming?

In recent years, scientists have debated whether human-caused global warming is affecting hurricanes by making them stronger or causing them to occur more frequently.

In theory, warmer atmospheric temperatures should lead to warmer sea surface temperatures, which should in turn support stronger hurricanes.

The number of Category 4 and 5 hurricanes worldwide nearly doubled from the early 1970s to the early 2000s. Moreover, both the duration of tropical cyclones and their strongest wind speeds have increased by about 50 percent over the past 50 years.

But there is no scientific consensus on a link is between climate change and hurricanes.

"Average tropical cyclone maximum wind speed is likely to increase, although increases may not occur in all ocean basins," according to the 2012 Intergovernmental Panel on Climate Change report.


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