Weather Academy: What Makes Flash Flooding So Dangerous?

Published: Mar. 21, 2022 at 5:57 AM CDT
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MONROE, La. (KNOE) - Good morning, and welcome back to the weather academy! Today we are talking about one of the deadliest weather phenomena, flooding. Flooding was the second-highest cause of weather-related deaths behind the heat in the last ten years.

Flash floods are the most dangerous floods because they combine destructive power with incredible speed. Flash floods occur when heavy rainfall exceeds the ability of the ground to absorb it. If our ground is already saturated, the water won’t be absorbed into the soil and can pool into the street. Urban areas are more prone to flash floods because they have more concrete that increases runoff by reducing the amount of rain absorbed by the ground. Flash floods can also happen within minutes of the heavy, high-intensity rainfall, limiting the time available to warn and protect the public. Also, if we see extended periods of heavy rain, water can quickly overwhelm drains and begin to flood the surrounding areas.

Heavy rain can lead to rapidly rising water in low-lying areas. Only 6 inches of water is enough to knock a person off their feet. If we continue to see the water increase to 12 inches, that’s enough to move a car or SUV. By the time the water reaches a height of 18 inches, large vehicles are at risk of being swept away. That’s why we always say, turn around, don’t drown. You never want to drive through flooded roadways. During flash flood warnings, try to seek high ground if you are on foot and take these warnings seriously because flash flooding can happen in a matter of moments.

Another reason why we say turn around, don’t down, is because you never know what has been swept up in the floodwaters. Large branches, trees, and debris can all be invisible hazards that you can’t see lying underwater.

One way that you can help reduce the risk of flash flooding before rain moves in is to make sure that you keep storm drains clear of leaves and other items that could clog them and cause poor water drainage. Clean drains will allow for roads to stay clear of pooling water.

Thank you for joining us on this week’s Weather Academy segment. Make sure you tune in next week because Sheena and I will be putting our engineering skills to the test as we try out a flash flooding experiment.

Click here to learn more about the science behind weather and see fund experiments you can do at home with your kids!

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