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27 Storms: Arlene to Zeta
Let's exam what made conditions so
favorable for Atlantic storm formation in 2005.
We begin with the ocean;
these are sea surface temperatures for the 2005
hurricane season, changing through time as the calendar advances.
Warm water powers hurricanes, orange and
yellow areas, shows zones with water warmer than 82
degrees; the threshold favorable for hurricane development.
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Let's start the season again,
this time adding clouds back into the picture.
Atlantic basin hurricanes typically form between June
and November.
Hurricanes often start as
atmospheric disturbances off the coast of West Africa.
Once out into the warm summer waters of the Mid-Atlantic,
some ripples begin to rotate,
and feeding off of warm water, strengthen into hurricanes.
Hurricanes require warm water to heat
air above the ocean causing a drop in air pressure.
Lower air pressures sucks more water vapor
into the storm, causing storms to strengthen.
As hurricanes pass over warm water,
they leave trails of relatively cooler water,
so-called cold water trails.
Numbers displayed over storm tracks
indicate hurricane category changes.
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Strong shearing winds in the troposphere can disrupt this process,
weakening young storms, but measurements indicate
that there was very little shearing wind activity in 2005
to impede storm formation.
Hurricanes are rare phenomena;
only about 80 or 90 appear worldwide
every year.
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Storms stalked the Atlantic Ocean and Easter Seaboard from June
until early winter in 2005 and the record books are
groaning under the strain of such a busy year.
Consider this list of superlatives.
An average year produces roughly 10 storms,
27 named storms formed in 2005.
An average year produces six hurricanes,
15 formed in 2005.
An average year produces two major hurricanes.
Seven formed in 2005.
On average one category 5 hurricane forms every three years.
In 2005, there were three: Katrina, Rita, and Wilma.
Wilma was the most intense Atlantic hurricane ever recorded,
Katrina fourth, Rita sixth.
But Katrina was the most destructive hurricane ever to hit the United States.
The total losses from storms in 2005 include
more than 1,200 lives
and potentially more than 100 billion dollars.
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This visualization shows some of the
actual data that NASA and NOAA satellites measured this season.
Data used to predict the paths and intensities of hurricanes.
Satellite data play a vital role in helping us
understand the land, ocean, and atmosphere systems
that have such dramatic effects on our lives.
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