Hurricanes, Typhoons and Tropical Cyclones… Oh, My !

What Hurricanes are called around the World   Source: NASA

It was fascinating to hear people discuss tropical cyclones during my time in Australia.  While known as hurricanes in the Atlantic Ocean, Australians know hurricanes by a different name (“cyclones”).  While there is no difference in the physical structure of the storms, hurricanes are known by a few different names depending on what part of the world they form in.  

In the Atlantic Ocean Basin (that includes the Atlantic Ocean north of the Equator, the Gulf of Mexico and Caribbean Sea) as well as the Pacific Ocean from the West Coast of North America to the International Date Line, hurricanes are simply known as “hurricanes.”  Once you travel west of the International Date Line, a hurricane is known as a “typhoon.”  Meanwhile in the South Pacific Ocean near Australia, Indian Ocean and the Bay of Bengal, hurricanes are known as “cyclones.”  A tropical storm becomes a hurricane when sustained winds reach 74 mph.

A significant portion of the Australian coastline experience cyclones from time-to-time.  People I spoke with remembered Cyclone Maria as a significant storm in April 2006, much like Cyclone Chris was in February 2002.  The Australian government’s Bureau of Meteorology has detailed records of the strongest and most destructive tropical cyclones to impact the continent.  Besides the United States and Australia, some other countries that have government agencies dedicated to forecasting tropical cyclones include Japan, India and Indonesia. 

A tropical cyclone is general term for a cyclone that originates over the tropical ocean and includes tropical depressions, tropical storms and hurricanes.  The strongest tropical cyclone on record was Typhoon Tip in 1979 that had a minimum central air pressure of 870 millibars (mb).  By comparison, standard sea level air pressure is approximately 1013.25 mb.  The Atlantic Ocean’s strongest hurricane was Hurricane Wilma in 2005 with a minimum central air pressure of 882 mb.  Air pressure is generally considered a more accurate measure of tropical cyclone intensity than wind speed.  Hurricane Patricia had the highest sustained winds on record in any tropical cyclone (215 mph) in 2015.  Tip, Wilma and Patricia all reached Category 5 status on the Saffir-Simpson Scale at peak intensity. 

Due to generally unfavorable conditions, hurricanes don’t typically form in the south Atlantic or the Pacific side of South America.  However, in March 2004 Hurricane Catarina became the first hurricane to make landfall in Brazil.  It formed in an area of favorable conditions with low wind shear and above average sea surface temperatures.  Catarina was a Category 2 hurricane at its time of landfall with sustained winds of 100 mph.  That was the only hurricane on record to develop in the South Atlantic Ocean.