
| HOME | Hurricane Threats | Saffir-Simpson Scale | Hurricane Preparation | HAZARD ANALYSIS |
Hurricanes
are tropical cyclones in which winds reach constant speed of 74 miles per
hour or more, and blow in a large spiral around a relatively calm center
(the eye of the hurricane). Hurricanes
are very large whirlwinds in which air moves in a tightening spiral around
a center of extreme low pressure, reaching maximum velocity in a circular
band 20 30 miles or
more from the rim of the eye. Near
the center winds may gust up to 200 miles per hour with hurricane force
winds (74 mph or greater) reaching to more than 100 to 150 miles from the
center.
Storm
surge is the greatest cause of deaths during a hurricane.
Some surges reach 20 feet or more in height causing millions of dollars
in damages from beach erosion, undermining roads, bridges, railroads, and
structures along the waterfront.
Hurricane Structure
The main parts of a hurricane (shown below) are the rainbands on its outer edges, the eye, and the eyewall. Air spirals in toward the center in a counter-clockwise pattern, and out the top in the opposite direction. In the very center of the storm, air sinks, forming the cloud-free eye.
The Eye
The hurricane's center is a relatively calm, clear area usually 20-40 miles across. People in the midst of a hurricane are often amazed at how the incredibly fierce winds and rain can suddenly stop and the sky clear when the eye comes over them. Then, just as quickly, the winds and rain begin again, but this time from the opposite direction.
Polk County is located a little over 100 miles inland and is not effected by storm surge, however, torrential rains, tornadoes and high winds cause huge losses. Torrential rains have been known to produce up to 30 inches of rain or more, these rains cause severe flashfloods and riverine flooding along the river basins of the Trinity and Neches Rivers. High winds cause trees to topple on houses and across power lines and roadways.
A prime example is Hurricane Jerry in 1989.
Jerry was a minimum category one hurricane that devastated
the Southern and eastern parts of Polk County.
About half of the residents in these areas were without electricity
for 5 to 10 days. Trees were
downed everywhere blocking roads and destroying houses.
Hurricanes do not have to strike Southeast Texas to impact
Polk County, Storms as far away as Corpus Christi can spawn tornadoes and
produce torrential rains of 8 10 inches or more.
The
upper Gulf Coast has enjoyed an unprecedented population explosion, with
growth exceeding better than 57%
over the past five years. With
this tremendous growth rate we are faced with many new problems, such as,
a great many of the residents have very little or no hurricane experience.
The Upper Gulf Coast has not been impacted by a major hurricane in
over fourteen years, residents feel safe and have grown complacent and do
not heed evacuation warnings. Projected traffic density along evacuation routes can
create a condition that may preclude a safe evacuation, as many Southeast
Texans experienced during Hurricane Andrew.
Even though Hurricane Andrew turned and did not impact the Texas
Coast, many Texans that evacuated from the Golden Triangle found themselves
stranded for hours on end in dense traffic
Three
evacuation routes cross into Polk County, US 59 that runs North from the
Houston area, Texas 146 that runs North from the Galveston area, and FM
1276 that runs North from FM 105 out of the Beaumont area.
All of these routes come together in Livingston causing a gigantic
bottleneck. (see Attachment Evacuation Routes in Polk County). There is a concern that if:
Ø
The Galveston Houston area has an evacuation
and
Ø
The Golden Triangle (Beaumont, Orange and Port
Arthur) areas evacuate.
Both
areas evacuating at the same time will cause a traffic Nightmare
for Polk County. This would be a worst case scenario.
(See Attachment 6 A for Hurricane Evacuation Routes.)
Below
is a list of hurricanes that have affected Polk County over the past fifteen
years.
Year |
Date
|
Hurricane Name |
Classification
|
Maximum Winds
(mph) |
1983 |
Aug. 18 |
Hurricane
Alicia |
Category
3 |
115 |
1986 |
June 26 |
Hurricane
Bonnie |
Category
2 |
97 |
1989 |
Aug. 1 |
Hurricane
Chantal |
Category
1 |
80 |
1989 |
Oct. 15 |
Hurricane
Jerry |
Category
1 |
85 |
|
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Information source,
National Weather Service and Polk County Enterprise
This Homepage was prepared by Kenneth F. Hambrick, Polk County
Coordinator. Contact at E-Mail address: webmaster@pcoem.org
for additional information about our program. The information contained
in this Homepage is considered public domain and the Office of Emergency
Management encourages interested persons to utilize any portions of it that
might be of educational benefit or enhance their local programs.
