Flash Flood — Humphreys, Tennessee

2021-08-21 · near Pigeon Roost, Humphreys, Tennessee

Event narrative

An historic, devastating flash flood struck the city of Waverly along the Trace Creek river basin. A fast-moving flood wave traveling westward down Trace Creek caused flood waters to rise several feet in roughly a 10 minute timespan between 1000am to 1010am CDT, flooding hundreds of homes, businesses, and churches, some of which were washed off their foundations. News reports and information from the Tennessee Emergency Management Agency indicated a total of 523 homes were impacted by the flooding, with 272 totally destroyed, 168 with major damage, 31 with minor damage, and 20 affected. 44 businesses and 8 public facilities were also damaged, including the Waverly Elementary School and Waverly Junior High School which will have to be torn down are rebuilt in a different location. Dozens of cars were also washed away and deposited long distances downstream, and many of the roadway bridges than spanned Trace Creek were knocked off their pilings and heavily damaged. TEMA reported damage to roads and schools alone totaled $31,844,911, with an additional estimated $60-70 million in damage to homes and businesses. 19 people were killed in Waverly, along with 1 other who died in Hurricane Mills, making this the deadliest flash flood in Middle Tennessee history.

Wider weather episode

The deadliest flash flood to ever affect Middle Tennessee, and one of the worst natural disasters in the history of the state, struck the region on Saturday, August 21, 2021. Occurring only a few months after another deadly and disastrous flash flood impacted the Nashville metro area on March 27-28, 2021 and killed 7 people, this flash flood left catastrophic damage across several counties in western Middle Tennessee, including parts of Dickson County, Hickman County, Houston County, and especially Humphreys County. The flood waters damaged or destroyed hundreds of homes, businesses, vehicles, and schools, with many buildings washed completely off their foundations. The damage was so severe that a Presidential Disaster Declaration was declared for Humphreys County two days later on August 23, 2021. Later in the week, Dickson, Hickman, and Houston Counties also received a Presidential Disaster Declaration. Very sadly, a total of 20 people were determined to have drowned in the flood, 19 of which were in the city of Waverly, TN, and 1 in the community of Hurricane Mills.

This historic flash flood occurred as a thunderstorms repeatedly developed along a weak surface front located over western Middle Tennessee during the morning hours of August 21. With a very moisture-laden atmosphere in place characterized by precipitable water values measured at 2.37 inches on the 12Z OHX upper air balloon sounding, these thunderstorms produced extreme rainfall rates over 3 inches per hour for several hours, resulting in rainfall totals reaching over 10 to 20 inches in a narrow, roughly 25 mile wide by 50 mile long swath across Houston, Dickson, Humphreys, and Hickman Counties. A rain gauge at the McEwen Wastewater Treatment Plant measured a rainfall total of 20.73 inches from midnight to 7pm CDT, which was verified by NWS personnel and set a new Tennessee state record for 24-hour rainfall. In addition to the flash flooding, one brief tornado was determined to have touched down in rural Dickson County northwest of Charlotte.

View location on OpenStreetMap → (36.0852, -87.8281)

Source: NOAA Storm Events Database, event_id 982536. Narrative written by the NWS forecast office that issued the report.