Weekly Online Lesson Online Lesson Archive Grade Level: 8-12 Subject: Science

Life in the flood zone

Weather forecasters expect the first hurricane and related conditions to occur around June 1 every year. Residents who live near the coasts of the Atlantic Ocean and the Gulf of Mexico know every season, they always face the risk of being battered by a hurricane's intense winds that whip through the landscape at over 74 miles per hour. During the first week of June this year, folks were fortunate that no hurricane formed, only a tropical storm that hit the southeastern coast of Texas. But although Tropical Storm Allison didn't bring the severe wind speed of a hurricane, the 20 inches of rain she dropped on the Houston area caused severe flooding, which resulted in 11 deaths and the destruction of thousands of buildings.

The risk of floods doesn't just exist in the marine coastal areas, either — there's risk wherever rivers flow. And because people need easy access to water — for farming, drinking, shipping goods, etc. — they have tended to build their homes in areas adjacent to a river. The government and related agencies have created ways to predict flooding conditions, which helps people be more prepared for them, but some floods become so severe that all attempts to stop them are futile.

In this week's lesson, you'll read about several historical floods, why floods occur and how people try to monitor and predict potential flood conditions.

Not ready for the rain

Start your lesson at The Weather Channel, reading about How Floods Occur. You'll learn about different kinds of floods and why they happen. Also, look at the map to see which areas in the U.S. are most at risk for flooding. Do you live in one of those areas?

Next, check out some of the most devastating Historical Floods and Flash Floods, including the Mississippi River Flood of 1993 that affected communities from Minnesota to Missouri. You can also read the stories about the Johnstown Flood of 1889 in Pennsylvania, the Big Thompson Flood of 1976 in Colorado, and the Shadyside Flood of 1990 in Ohio. How early before the river breached its banks did weather forecasters predict it? How quickly did the flooding occur after the rainfall began? How much of an area did the flood affect?

Measuring Risk

Although such devastating floods seem inevitable, knowing what causes them and constantly monitoring the weather and river conditions can at least give residents warning in advance so they can either prepare to fight or leave the area. Learn about how scientists Forecast Floods, by Gathering Flood Data on the changes in river flow. What kinds of different information do they use and how do they get it? Also read about how the different agencies, such as the River Forecast Centers and Integrated Flood Observing and Warning System, gather data for cooperative Flood Research.

Visit the Storm Prediction Center's Watch, Warning and Advisory Display to find out daily where the risk of flood is rising, and keep track of the month's floods and flood warnings through the National Weather Service's Flood Summary.

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