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Understanding the Full Flood Life Cycle Can Help You Prepare for an Emergency

September 23, 2020

According to National Geographic, floods are the Earth’s most common and most catastrophic weather events. Floods happen when an area that is normally dry gets more water in a short period of time than can be absorbed back into the ground, rivers, and streams. This can be caused by extreme rainstorms, the rapid melting of snow or ice, or a broken man-made dam. For coastal areas, flooding can be caused by a hurricane or monthly tidal changes.

Some floods happen gradually over time, allowing local areas to prepare and evacuate, but others happen with little to no warning. These major weather events are increasing around the world in response to climate change. More than 670 communities in the U.S. will be impacted by repeated flooding events by the end of this century, according to new reports. That’s in addition to the coastal communities that are already seeing catastrophic flood damages.

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Flood impacts and preventions

In the U.S., floods cause $8 billion in damages each year. Once floodwaters recede, homes and entire communities are left with extensive clean-up costs. In addition, hazardous contaminants are brought by floodwaters into homes, businesses, and local ecosystems. From fuel to sewage and large debris, floodwaters can leave extensive, costly damages in their wake. Residents affected by flooding often lose clean drinking water and power, making recovery efforts even more difficult.

To prevent floods, communities are banding together to build new infrastructure. Homeowners are purchasing costly flood insurance and building more flood-resistant homes.  For example, in New Orleans, a levee system was created after extensive hurricane-related flood damages. According to the U.S. Army Corps of Engineers, the flood risk management life cycle includes preparation, response, recovery, and mitigation. This flood prevention checklist for homeowners is a great place to start preparing for a flood to minimize the costly impacts on your home and your wallet.

A Flood Life Cycle Example: The 2015 Texas Flood

NASA documented the full flood life cycle of the 2015 Texas flood, including how it impacted ecosystems both on land and water. To do this, scientists used satellites and soil moisture instruments to trace the event, from rains that started weeks before to lingering impacts to wildlife in the Gulf of Mexico months later. From May 23-25, 2015, enough water fell to cover the entire state with eight inches of water. The flooding it caused impacted home and business owners and marine life, and 11 people were killed.

Because the Texas soil was already waterlogged, the rain had nowhere to go but downstream. NASA found that eight rivers drained water into the Gulf at a rate as high as 1,700 cubic meters per second during the peak of the storm. The freshwater plume it caused was measured as far away as Louisiana. In addition to the record rainfall, snowmelt from earlier in the year added to the amount of water in the Mississippi River. The river water also carried pollutants into the Gulf and nutrients that increased algae growth, impacting fish and plant life. After the 2015 flood, the zone grew 28% larger than average. The “dead zone” in the Gulf created by events like the Texas flood impact the fishing industry for one of the largest providers of seafood in the U.S.