Risk Assessment for Flash Flooding
As a result of the disastrous flash floods in Kerr County Texas, many Americans are concerned with the risk of flash flooding. According to the National Weather Service, a flash flood is: flooding that begins within six hours, and often three hours, of heavy rainfall or another flood water source.” These floods usually happen because the water is not draining as fast as it is moving in, which also results in water flowing quicker than normal, causing more hazards to human life. Unlike other flood types, these are quickly occurring, making preparation more difficult.
In the Quad Cities region, we often think of the Mississippi River when it comes to floods. However, flash floods do not impact the Mississippi Rivers in comparison to rivers in valleys, streams, creeks, and even streets. The last major flash flood the Quad Cities experienced was in 1990 in Duck Creek. Rainfall amounts were higher and longer lasting that spring, and because of development along the creek bed, one thunderstorm in particular brought 9 inches of rain in a few hours, causing the bed to rise suddenly and damage nearby buildings.
Although flash floods can happen in many places, there are ways to assess your risk. The topography, ground cover, and soil conditions are additional factors that can affect flash floods. Steeper terrain is more susceptible to flash floods due to water flowing downhill. Impervious surfaces, such as buildings, parking lots, and many streets, don’t allow for water to soak into the ground, which will increase runoff and the chance of flash floods. If you live in an area that sounds similar to that description, pay attention to strong storms and what to do in the case of flooding.
In the case of a flash flood, there are things you can do before and after to protect yourself and loved ones. Beforehand, pay attention to the radio and TV for weather information, which will make citizens aware of a flash flood watch or warning. Know your area’s flood risk by reaching out to your local emergency management agency or the National Weather Service. River Action has flood resources for thirteen municipalities in the Quad City region listed on its website, providing citizens with people to reach out to, ways to mitigate floods, and more. Have a family disaster plan to plan on evacuation, if you are separated, and reconnecting. The Red Cross has more resources on its website on how to make a family disaster plan. If a flash flood is a possibility, stay away from areas that are known to flood, if possible. During a flash flood, stay away from moving water. Six inches of fast moving water is enough to make a person fall, and twelve inches can carry away most cars. Get to higher ground as soon as possible.
Flash floods are fast, strong and dangerous. Knowing the risk and what to do in the event of a flood is one of the most important things to do in order to protect yourself from the #1 weather-related killer in the United States. For more information, visit weather.gov, redcross.org, or riveraction.org/flood.