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HURRICANE GUIDE
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K8 H O U S T O N C H R O N I C L E
Thursday, June 1, 2006
Hurricanes, the big picture
The 2005 hurricane season was a record-breaking one,
with 28 named storms, including 15 hurricanes, seven
of them major. Here's how, why, when and where
hurricanes form.
CYCLONIC STORMS WORLDWIDE
Even though Atlantic Ocean hurricanes receive a lot of attention, only 12 percent of tropical
cyclones seen worldwide are located here. The diagram below shows the regions of the
Earth where tropical storms originate and the percentages of the total worldwide.
Western
Atlantic
Ocean
12%
12%
15%
East
Pacific
Ocean
30%
12%
South
Indian
Ocean
Cooling down
12%
7%
Dominant paths
Some hurricanes reach northern
latitudes and as water gets colder,
they weaken and fade away.
However, in some rare cases
storms have even
reached Europe.
LIFE CYCLE OF
A HURRICANE
Western
North Pacific
Ocean
North Indian
Ocean
South
Pacific
Ocean
North and
West Australia
Regions where
hurricanes originate
TEXAS IN THE CROSSHAIRS
Texas is second only to Florida in the number of hurricanes making
landfall since 1851. Most of Texas’ hurricanes have been category 3 or lower.
1 Tropican wave (Day1)
5 Strike (Day11)
Once the hurricane
gets inland it
starts losing steam.
Even so, a storm
can survive several
days after striking the
coast dropping
significant amounts
of rainwater.
Hurricanes often form
from tropical waves, which
are simply ripples or
disturbances in the mean
wind flow. In the Atlantic
Basin, these waves normally
originate off the coast of
West Africa.
New York
Hurricane direct hits (1851-2004)
Texas hits by category
23
Florida (110)
17
Texas (59)
Louisiana (49)
S. Carolina (31)
Bermuda High
A high presure area that
spins clockwise. This giant
atmospheric disturbance
drives hurricanes in
a loop.
7
Alabama (22)
New York (12)
n
Cat 1 Cat 2 Cat 3 Cat 4
Oc
ea
Charleston
12
ic
Houston
la
nt
HURRICANE SEASON
At
The official hurricane season for the Atlantic Basin is from
June 1 to November 30. As seen in the chart bellow,
the season peaks in september.
Miami
Gulf of
Mexico
Number of storms per 100 years
2 Tropical depression (Day3)
A group of thunderstorms
come together under the right
conditions for a long enough
time, they may get
organized. Winds near the
center are constantly
between 23 - 39 mph.
Caribean Sea
4 Hurricane (Day 8)
A tropical storm, fueled by
warm water, becomes
a hurricane when sustained
wind speeds reach 74 mph.
A pronounced rotation
develops around the
central core.
3 Tropical Storm (Day 5)
A tropical depression has intensified
to the point where its maximum sustained
winds are between 39-73 mph. It is at this
time that it is assigned a name. The storm
becomes more organized and begins to
become more circular.
Magenta
Yellow
Rita (2005)
Aug.
Sep.
Oct.
Dec.
Category 1
Category 2
Category 3
Frederic (1979)
LOUISIANA
Georges (1998)
Ethel (1960)
Danny (1985)
Camille (1969)
Babe (1977)
Juan (1985)
Lili (2002)
Hilda (1964)
Andrew (1992)
Alicia (1983)
Bonnie (1986)
Katrina (2005)
Danny (1997)
Cindy (2005)
Florence (1988)
Betsy (1965)
Carmen (1974)
Bob (1979)
The eye
At the center of the storm, air
cools down and sinks, preventing
the formation of rain. In this area
the storm's lowest pressure
readings are obtained.
Eyewall
Category 5
Agnes (1972)
Kate (1985)
Alma (1966)
Dora (1964)
David (1979)
Erin (1995)
Eloise (1975)
Earl (1998)
Jeanne (2004)
Easy (1950)
Gladys (1968)
Outflow
The high level clouds moving clockwise
out away from the hurricane. These clouds are
indicative of air spreading out over the top of the
storm, which is essential to its development.
Donna (1960)
Katrina
(2005)
Andrew
(1992)
King
(1950)
Isbell (1964)
Wilma (2005)
Georges (1998)
Irene (1999)
Floyd (1987)
Donna (1960)
A band of clouds, strong winds and
heavy rains surrounding the eye
of the storm. At the eyewall, there is
rapid movement of air toward the
center and upward into the cloud.
Inez (1966)
Betsy (1965)
Right-front quadrant
3,500 ft
Rotation
Frances
(2004)
Cleo
(1964)
FLORIDA
Charley (2004)
ANATOMY OF A HURRICANE
MEXICO
Category 4
Florence (1953)
Danny (1997)
Edith (1971)
Beulah (1967)
7 8 9 10 11 12
Jun.
Flossy (1956)
MISSISSIPPI Baker (1950)
Audrey (1957)
Allen (1980)
y
0
Ivan (2004)
Jerry (1989)
Fern (1971)
20
Erin (1995)
Chantal (1989)
Debra (1959)
Celia (1970)
Carla (1961)
Bret (1999)
40
Dennis (2005)
Houston
Claudette (2003)
60
Opal (1995)
Cindi (1963)
TEXAS
Hurricanes
ALABAMA
m
Hurricanes and tropical storms
80
May
HURRICANE STRIKES (1950-2005)
The map bellow shows all the storms that
directly hit the states of the Gulf of Mexico
in the last 55 years. Hurricanes Camille,
Andrew and Katrina are some of the most
intense and destructive in recorded history.
100
Also know as the “dirty side” of
the hurricane, has the added force
of the storm’s foward movement
which increases wind speed.
In the Northern Hemisphere
hurricane surface winds spin
counterclockwise toward the eye.
Feeder bands
Squally bands of showers characterized by
strong gusty winds and heavy rains. These
bands become more pronounced as the storm
intensifies, and are fed by the warm ocean.
THE SAFFIR-SIMPSON SCALE
The Saffir-Simpson Hurricane Scale is a 1-5 rating based on the hurricane's present intensity. Wind
speed is the determining factor in the scale, as storm surge values are highly dependent on the slope
of the continental shelf and the shape of the coastline, in the landfall region.
Cyan
74-95 mph
96-110 mph
111-130 mph
131-155 mph
More than 155 mph
c
Category 1
Category 2
Category 3
Category 4
Category 5
Damage primarily to
unanchored mobile homes,
shrubbery and trees. Some
coastal road flooding and minor
pier damage.
Some damage to roofs,
doors, windows, trees
and shrubbery. Flooding
damage to piers
Some structural
damage; large trees
blown down; flooding near
shoreline and possibly inland;
mobile homes destroyed.
Extensive damage to
doors and windows;
major damage to lower floors
near shore; terrain may be
flooded inland.
Complete roof failure
and some building
failures; massive evacuation; flooding
causes major damage to lower floors
of all shoreline buildings.
Sources: NOAA, University oif Illinois.
ALBERTO CUADRA : C H R O N I C L E