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Dear
Marlee,
In
the early days of hurricane tracking in the North Atlantic
Basin, which includes the Atlantic Ocean, Caribbean Sea and
the Gulf of Mexico, memorable storms were often named after
the places where they made landfall (for example, Florida
Keys Storm of 1935). Weather observers later used latitude
and longitude positions to identify the storms, but this system
was confusing and difficult to use in radio broadcasts. The
National Weather Service began assigning names to the storms
in 1950 based on a phonetic alphabet system (Able, Baker,
Charlie, etc.). In 1953, the National Weather Service replaced
the old system with a new, international phonetic alphabet,
and then developed an official list of hurricane names that
included only female names. This practice continued until
1979 when male and female names were alternated on the list.
Today,
an international committee of the World Meteorological Organization
manages the naming system, which includes making lists of
storm names for the Atlantic Ocean, the Pacific Ocean, and
the Indian Ocean. For Atlantic hurricanes, six different lists
are used in rotation. Each list starts with a name that begins
with the letter “A” and ends with a name that begins
with the letter “W”. Also, each list alternates
between starting with a male or female name. A new list is
used at the beginning of each hurricane season (June 1 to
November 30) so that the name of the first storm of the year
always begins with “A”. At the end of six years,
the first list is recycled and the process starts all over
again. In many regions of the world, however, the lists are
not rotated until all the names are used. Rotating these lists
means that many names are used again and again, but famous
names like Hurricane Andrew (1992) and Hurricane Camille (1969)
are retired forever.
The
Atlantic Hurricane season extends from June 1 to November
30, with September being the peak month for hurricane activity.
Hurricanes begin to form when the sea surface temperature
reaches approximately 80 degrees Fahrenheit. Therefore, most
hurricanes in the early part of the season (before Labor Day)
form in the Caribbean Sea and Gulf of Mexico because these
water bodies are relatively shallow compared to the Atlantic
Ocean, and thus, warm up more rapidly. This pattern leads
to more hurricane landfalls in the U.S. along the Gulf of
Mexico coast during the early part of the season. After Labor
Day, hurricane formation shifts eastward as the Atlantic Ocean
begins to warm up, which leads to an increase in hurricane
landfalls along the U.S. Atlantic Coast in September and October.
Late in the season, the Atlantic begins to cool so hurricane
formation shifts back to the Caribbean and Gulf of Mexico
region.
The
word hurricane comes to us from the Caribbean region, where
the Carib Indians used the term “huaracan” meaning
“big wind.” In the Pacific Ocean region hurricanes
are called Typhoons, which appears to come from the term “Tai-phung”
that also means big wind. In the Indian Ocean region, hurricanes
are simply referred to as “Cyclones,” which refers
to their meteorological definition as a low-pressure weather
system with a cyclonic rotation. Interestingly, the earth’s
rotation around its axis causes wind flow patterns in the
northern and southern hemisphere to be reversed. So hurricanes
that hit the U.S. rotate in a counter-clockwise direction
while Cyclones that hit places like Australia in the southern
hemisphere rotate in a clockwise direction.
Thanks
for your question,
Aubie and Dr. Chaney
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