Geography Reference
In-Depth Information
In 1982-83, El Niño was unusually dramatic, a whole 7˚C warmer than normal water temperature
ranges, pumping more heat energy into the atmosphere. A period of unusual weather at the time has been
called the most disastrous in recorded history. Weather patterns were altered across three quarters of the
globe, causing floods along the western coasts of both South and North America, and droughts in southern
Africa, South Asia, and Australia. There were massive die-offs of fish, sea birds, and corals, and the hu-
man toll of El Niño was put at more than a thousand dead.
The 1990s edition seemed kinder and gentler. But it is still exerting strange effects on the world's
weather. Again, some places were more rainy than usual. In others, drought conditions worsened. Although
it was first recognized in 1726, El Niño is still little understood and no single theory for the once-in-a-dec-
ade warming is widely accepted.
NAMES: Cyclone, Hurricane, Typhoon, Tornado
“It's a twister!” At least it was in
The Wizard of Oz.
But what was Dorothy Gale's Kansas “twister”—a
tornado or a cyclone? And what are the differences anyway?
By any name, these storms can be deadly. In April 1991, a cyclone in Bangladesh left 138,868 dead
and millions homeless. Hurricane Gilbert, which hit the Caribbean and the Gulf coast of the United States
in 1988, killed at least 260 people. In 1984, Typhoon Ike hit the Philippines, and more than 1,300 people
died. A 1974 tornado killed more than 300 people in the American Midwest.
All four types of storms are variations on a true cyclone, a word that is used in both a specific and
a general sense. A true cyclone is technically a windstorm with violent, whirling winds rapidly circulat-
ing around a low-pressure center—the “eye” of the storm. Cyclones are accompanied by stormy, often
destructive weather. (In the Northern Hemisphere, the cyclone winds circulate counterclockwise; in the
Southern Hemisphere they move in a clockwise direction.)
Hurricanes, typhoons, and cyclones are all the same kind of violent storm originating over warm ocean
waters and called by different names all over the world.
Hurricane
(derived from a Carib Indian word)
is typically used to describe these storms when they originate in the tropical Atlantic Ocean or Caribbean
Sea. The huge whirling mass of cloud which rotates around the calm “eye” may be over 248 miles (400
km) across. The spiraling winds may reach from 9 to 24 miles (15 to 20 km) up into the atmosphere. A
typhoon
(from the Cantonese word
tai fung
) is a violent tropical cyclone originating in the western Pacific,
and especially the South China Sea. When these storms originate in the area of the Indian Ocean, they are
called
cyclones
.
A
tornado
(an alteration of the Spanish word
tronada
, for “thunderstorm”) is also a form of cyclone.
A violent twisting funnel of cloud that extends down to land from a large storm cloud, a tornado covers a
much smaller area than a hurricane. But it is often more violent as it rushes across the land at speeds of 18
to 40 miles (30 to 65 kilometers) per hour.
What Is a Monsoon?
Monsoon
comes from the Arab word
mausim
, which means “season.” The word is used for the heavy rain
that occurs in some parts of the world, especially in South and East Asia. This rainy season begins sud-
denly when winds from the sea sweep across the land. More than half the world's population lives in areas
with monsoon climates. And most of these are the poor regions in which most of the people depend on
agriculture for survival. A late or failed monsoon season can mean disaster and starvation.
