Wednesday, September 21, 2011

Society’s Vulnerability to Natural Hazards by Carol Wilks

Flash Floods

PHS 100A Environmental Studies
Warner Pacific College

September 20, 2011

Society’s Vulnerability to Natural Hazards

As a child, I experienced a flash flood while visiting relatives in Savannah, Georgia. My memories of the flood bring a smile to my face as I recall the boys who were on their surfboards in the golf course behind Uncle Bubba’s and Aunt Mary Nell’s house. The only thing scary about it to me was that I couldn’t get to my mom who was at Granny’s on the other side of town, and she couldn’t get to me. I was too young to be aware of the possible dangers surrounding us.

The natural hazard known as a flash flood can be especially dangerous because of its sudden formation and potential widespread destruction. Flash flooding occurs when precipitation falls too quickly on saturated soil or dry soil that has poor absorption ability. The runoff collects in low-lying areas and rapidly flows downhill. Cities located along rivers or beneath dams are especially vulnerable if the amount of water generated during a flash flood overwhelms protective barriers.

Of the deaths that occur due to flooding, nearly half of all flash flood deaths are those of people in vehicles. The United States National Weather Service gives the advice "Turn Around, Don't Drown" for flash floods, recommending that people turn around and get out of the area of a flash flood, rather than trying to cross it. The mistake that many people make when it comes to low-lying flood waters is thinking that it’s not too deep. It takes only 18 to 24 inches of water to float a car or SUV. Once a vehicle is afloat, its tendency is to turn sideways and roll over, trapping the people inside. More people lose their lives in flooding than in any other weather related event (NOAA’s National Weather Service).

On average, flooding causes over $2 billion of property damage each year. Flash floods can roll boulders, tear out trees, destroy buildings and bridges, while scouring out new channels. Rapidly rising water can reach heights of 20 feet or more (NOAA’s National Weather Service). Furthermore, flash flood-producing rains can also trigger catastrophic erosion, producing mud slides that take out roads, homes, and businesses. Many people have been left homeless by flash floods due to the fact that their homeowners insurance did not automatically include flood hazard coverage.

Ecosystems are affected by flashfloods through various ways. Erosion from flash floods can uproot trees and destroy riverbanks. These natural features normally provide protection from flooding, but once they are gone, the landscape is altered and the chance of further flooding is increased. Fish and wildlife are impacted by toxins from destroyed buildings that spread through the water, including paint, gas, and pesticides.

In the event of a flash flood, the Center for Disease Control lists ways to prevent injury during and after the disaster. These include avoiding wild animals and stinging or biting insects; using alternative sources of fuel for cooking, heating, or cooling to avoid possible carbon monoxide poisoning; avoiding electrical power lines; leaving a building immediately if you hear shifting or unusual noises that signal that the structure may fall or if you smell gas or suspect a leak; boiling water to drink or cook with (CDC).

My family was fortunate. Uncle Bubba’s and Aunt Mary Nell’s house sat up high enough that the flash flood didn’t reach us. We did have to wait a few days for the flood waters to subside to reunite with the rest of the family, and we did have to get typhoid shots when we returned home. But we were safe.


NOAA’s National Weather Service; retrieved Sept., 2011 from

NOAA’s National Weather Service, Southern Region Headquarters; retrieved Sept., 2011 from

The Effects of Flash Floods, retrieved Sept., 2011 from

Centers for Disease Control and Prevention, retrieved Sept., 2011 from

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