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A call to action to protect your past, your present, your future and, your peace of mind.

Tropical Cyclones
Tropical cyclones threaten the United States with their torrential rains, high winds, and flooding. Even after the wind has diminished, the flooding potential of these storms remains for several days.

Tropical cyclones are products of the interaction of oceans and atmosphere. Powered by heat from the sea, they are steered by the easterly trade winds and the temperate westerlies as well as by their own ferocious energy.

Since 1970, nearly 60% of the 600 deaths due to floods associated with tropical cyclones occurred inland from the storm's landfall. In fact, more people are killed by floods than any other weather related cause. Most of these fatalities occur because people underestimate the power of moving water.

In June 2001, Tropical Storm Allison deposited up to three feet of rain to the east and northeast of Houston, Texas during a 5-day period. This map of Harris County shows the heaviest rainfall distribution. Tropical Storms, such as Allison, have winds of 39 to 73 mph. So, the wind in Allison's case was not the cause of the destruction. In fact, tropical storms can produce more rain and flooding than the strongest hurricanes.

Types of flooding
Tropical cyclones can, and usually do, cause several types of flooding.
Flash flooding
Flash floods are rapid occuring events. This type of flood can begin within a few minutes or hours of excessive rainfall. The rapidly rising water can reach heights of 30 feet or more and can roll boulders, rip trees from the ground, and destroy buildings and bridges.
Urban/Area floods
Flooding from Tropical Storm Allison - ©2002 Harris County Flood Control DistrictUrban/Area floods are also rapid events although not quite as severe as a flash flood. Still, streets can become swift-moving rivers and basements can become death traps as they fill with water. The primary cause is due to the conversion of fields or woodlands to roads and parking lots. About 10% of the land in the United States is paved roads. So, water that would have been absorbed into the ground now runs into storm drains and sewers.
Coastal flooding
Coastal flooding occurs when strong winds blowing onshore, pushes water inland. In tropical cyclones, extensive damage occurs from storm surges when water, piled along the shore by the strong wind, rushes inland. See the Saffir-Simpson Hurricane Scale for the estimated damage by storm surges based upon the hurricane's strength.
River flooding
River floods are longer term events and occur when the runoff from torrential rains, brought on by decaying hurricanes or tropical storms, reach the rivers. A lot of the excessive water in river floods may have began as flash floods. River floods can occur in just a few hours and also last a week or longer.
Protecting yourself
While most floods cannot be prevented, there are simple steps you can take to protect your life and property. This is your call for action.

The things people most regret loosing in floods are valuables, such as jewelry, and items from their families past, such as photos and mementos. Even in the most severe floods, houses usually, houses are not completely submerged. A few simple precautionary steps now will help you save your memories. Simply hanging pictures a little higher on the wall will help diminish the threat of loosing them forever to floods.

Do you have extra photos laying around that may not be displayed? Where do you keep your photo albums? Are they close to the floor. if they are not on display, place them in plastic storage containers and store them in the attic. Have an extra, empty plastic storage container available to quickly gather jewelry, mementos, and other displayed photos and place the container in the attic should a flood emergency arrive.

Know your flood risks. Is your dwelling located near a creek or river? Where are you located in regard to your local terrain? Are on top of a hill, on the side of a hill, or in the valley. Purchase insurance through the National Flood Insurance Program. It will help you recover from a loss financially due to flooding. You will rest much better knowing your valuables are protected and the insurance will ease your recovery.

Flooding from Tropical Storm Allison - ©2002 Harris County Flood Control DistrictBefore a flood occurs, elevate expensive items such as outside air conditioning units. Seal vents to basements to prevent flooding. If a flood emergency is occur at your location, immediately shut off your electricity at the circuit breakers. This will prevent short circuiting electrical appliance such as refrigerators. In many cases with minor flooding, the refrigerator will just need to be cleaned and can be put back into use again. If the power was left on in a flood, the short circuit make repairs very costly.

Also, just because you may live thousands of miles from a flood, you could still be a victim. Vehicles that have been flooded are suppose to be salvaged but many are not. Unscrupulous people do superficial cleaning jobs on the vehicles and wholesale them to dealers across the nation. If you are considering purchasing a used vehicle, be sure to check the title history and hire a trusted mechanic to do a thorough inspection. A few dollars spent now could save your thousands of dollars down the road and maybe even you and your family's life.

Learn your evacuation routes! Remember you may need to know more than one way to escape rising water. Monitor NOAA Weather Radio to ensure you know the latest weather developments. Avoid driving on flooded roads so to not become stranded causing you to tie-up Emergency Rescue crews.

Additional resources
FEMA: National Flood Insurance Program | Flood Hazard Mapping | Flood Mitigation Assistance Program

National Weather Service: Flash Floods and Floods...the Awesome Power!

NWS Southern Region: Tropical Cyclones and Flooding Brochure (3.2 mb) | Requires the free Adobe Acrobat Reader

Lower Mississippi River Forecast Center: Flood Safety

Red Cross: Are You Ready For a Flood or a Flash Flood? (PDF)

  National Weather Service
  Southern Region
  Page last modified: July 29, 2003
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