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A man runs away as a wave breaks on a wharf in Shantou, China, during Typhoon Usagi.

Typhoon Usagi killed at least 25 people after crashing ashore in southern China on September 23.

Photograph from AFP/Getty Images

Ker Than

for National Geographic

Published September 23, 2013

A powerful typhoon that struck Hong Kong on Sunday killed at least 30 people and forced the evacuation of thousands of people on the China mainland, and hundreds of flights were canceled.

Typhoon Usagi — Japanese for rabbit — is the third and strongest Pacific typhoon to form this year. It was classified as a severe, or "super," typhoon after meteorologists recorded gusts of up to 160 miles per hour (260 kilometers per hour).

If you've never lived in Asia, you might be wondering what it feels like to experience a typhoon. But if you've ever survived a hurricane or cyclone, you already know the answer.

That's because hurricanes, cyclones, and typhoons are all the same weather phenomenon. Scientists just call these storms different things depending on where they occur.

In the Atlantic and northern Pacific, the storms are called "hurricanes," after the Caribbean god of evil, named Hurrican.

In the northwestern Pacific, the same powerful storms are called "typhoons." In the southeastern Indian Ocean and southwestern Pacific, they are called "severe tropical cyclones."

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 74 miles per hour (119 kilometers per hour).

If a hurricane's winds reach speeds of 111 miles per hour (179 kilometers per hour), it is upgraded to an "intense hurricane."

If a typhoon hits 150 miles per hour (241 kilometers per hour) — as Usagi did — then it becomes a "supertyphoon."

Different Seasons

While the Atlantic hurricane season runs from June 1 through November 30, the typhoon and cyclone seasons follow slightly different patterns.

In the northeastern Pacific, the official season runs from May 15 to November 30. In the northwestern Pacific, typhoons are most common from late June through December. And the northern Indian Ocean sees cyclones from April to December.

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 30 miles (48 kilometers) across, with some growing as large as 120 miles (200 kilometers) wide.

The strongest storms, equivalent to Category 5 on the Saffir-Simpson scale, have sustained winds that exceed 155 miles per hour (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. (Related: "Rising Temperatures May Cause More Katrinas.")

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. (Related: "Leaked Report Spotlights Big Climate Change Assessment.")

"It is likely that the global frequency of tropical cyclones will either decrease or remain essentially unchanged."

Follow Ker Than on Twitter.

30 comments
Dan Collyer
Dan Collyer

If you are interested the East Coast of Australia is about to be hit by a super storm, follow the link below for more info.I live in the cyclone Ita affected area, so i decided to start a blog video journaling the effects of the cyclone. I am hoping  & crossing my fingers my home remains intact. My Blog Is here if you want the latest from a local perspective! http://cycloneita.blogspot.com.au  

Alexis Fecteau
Alexis Fecteau

Yes there is a scientific consensus you idiots!  How dare you post non-scientific claims like that in an article, especially National Geographic, ufb!  Unless you don't consider 99% of all peer reviewed scientists a consensus.  Unless you claim that a few highly paid Exxon shills constitute legitimate opposition. 


I will never again read your publication. 

Alexis Fecteau
Alexis Fecteau

Yes there is a scientific consensus you idiots!  How dare you post non-scientific claims like that in an article, especially National Geographic, ufb!

ALEXANDER PERSEUS
ALEXANDER PERSEUS

Several questions:


1]  Is the term  a "twister" synonymous with "cyclone"?


2]  Are there "cyclones" in the US, e.g., the US state of Kansas, and if so, how is this [term] reconciled with the article's definition of a "cyclone", i.e., "In the southeastern Indian Ocean and southwestern Pacific, they are called "severe tropical cyclones." ?


Thanks in advance for your consideration. 

Dipak Kundu
Dipak Kundu

Classification of cyclonic  disturbances for the north Indian Ocean region for the exchange of messages among the Panel countries are given below :

Weather system Maximum wind speed

1.Low pressure area Wind speed less than 17 kt (31 km/h)

2.Depression Wind speed between 17 and 27 kt (31 and 51 km/h)

3.Deep Depression Wind speed between 28 and 33 kt (52 and 61 km/h)

4.Cyclonic storm Wind speed between 34 and 47 kt (62 and 88 km/h)

5.Severe cyclonic storm Wind speed between 48 and 63 kt (89 and

118 km/h)

6.Very severe cyclonic storm Wind speed between 64 and 119 kt (119 and 221km/h)7.Super cyclonic storm Wind speed 120 kt (222 km/h) and above

Indira Rao
Indira Rao

very useful information, Thanks!

Arpan Biswas
Arpan Biswas

We must try to give a check to global warming which is increasing the severity of such hurricanes or cyclones or typhoons.

Sam Arnold
Sam Arnold

i feel bad for that guy who is about to get rocked by that wave. 


Rock Beloved
Rock Beloved

I realy enjoy reading these information thanks for NG

Jeramy Rudolf
Jeramy Rudolf

I cannot agree to the assumption that it would be likely, that the global frequency of Tropical cyclones will remain unchanged or even decrease.

That is the same stuff that some people want to believe in order to prevent their bad conscience about the fact that we as mankind are responisble for those changes which now can be realised by everyone.

On my view: Nothing will get better through denying reality.

Derwin Lau
Derwin Lau

Incredible shot. But was the camera ok after a splash of saline water? 

Marry Field
Marry Field

I think it's too much dangerous to take picture like above...

Luis Perez
Luis Perez

Quite interesting description of these natural events.

Charles Becker
Charles Becker

"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 year"

Are these detectable or storms that reached the shore and/or do we have a pattern that relates the the changing currents and storm strength?  (every 20-50 years they increase / decrease) ?  

Just curious.  

Ah Mar
Ah Mar

thank you, now I know the difference.

jim adams
jim adams

Thank you .. that's one of those series of questions that i really wanted answered, but didn't know it until you provided the answers.



Sarah Wa
Sarah Wa

@Alexis Fecteau The author is not saying there is no link between climate change and hurricanes; there is just not scientific consensus about what that link specifically is and to what degree human activity has impacted the frequency and severity of severe storms. It's a question at this point of the extent to which human activity has impacted these storms (http://1.usa.gov/5jZ7D4). Researchers are looking into so many ways in which human activity affects the climate and there are so many different scales and methodologies, it's not totally unfair to say there is no scientific consensus (yet). I think before we jump to conclusions that publications such as National Geographic are being swayed by lobbyists, perhaps we need to take a breath and do a quick Google search (less than 30 seconds) to see if perhaps there could be some merit to what is being written. 

Chip Otley
Chip Otley

@ALEXANDER PERSEUS We call "twisters" tornadoes in the US; "twister" is an understood though lesser-used alternative.

"Cyclone" is a very old term for a tornado, and although some historical accounts use the term, is almost never used in common parlance.

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