Between midnight and 10:00 am CDT on Saturday, August 21, 2021, very heavy rainfall resulted in widespread flash flooding across western Middle Tennessee, including the town of Waverly.

The event resulted in 19 fatalities in Waverly, with another in nearby Hurricane Mills,[4][8] and is regarded as one of the worst natural disasters in Tennessee history.

[4] A stalled frontal boundary west of Nashville led to training thunderstorms during the early hours of August 21, producing very heavy rainfall rates across the counties of Stewart, Houston, Dickson, Humphreys, and Hickman.

Areas of Houston, central Humphreys, and northern Hickman counties still received upwards of 8 to 10 inches (200 to 250 mm) of rain during the event.

[12] The historic rainfall totals in McEwen and resulting flooding event in Waverly were compounded by a 300-foot (91 m) drop in elevation along Trace Creek as it flows westward into Waverly,[10] along with a CSX Bruceton Subdivision railroad bridge adjacent to U.S. Route 70–roughly one mile (1.6 km) east of town–that became blocked by debris, resulting in a temporary dam and lake forming.

The land under the railroad eventually gave way, sending a large tsunami-like wave into Waverly, with much of the town becoming inundated within the following five to twenty minutes.

Much of the floodwater exited the area westward along Trace Creek, causing large swells which inundated much of Waverly, just to the west.

Officials in Waverly commented that had the flood occurred during a weekday, the schools would have been full of students and would have been impossible to evacuate in time.

[19] Roads in Waverly such as U.S. 70, Tennessee State Route 13, and Main Street were rendered impassable into Saturday evening due to residual flooding and debris.

Numerous washed out and flooded roads prevented search and rescue and various news crews from arriving in Waverly until hours later.

[21][22] Numerous roads were impassable by high water or washed completely away during the flooding, especially around the Pinewood community, where a church was inundated and an RV park was swept away along the Piney River north of Nunnelly.

[24] The northern extent of the main area excessive rainfall and flooding was over the Jackson Purchase in Kentucky, specifically Calloway County.

[7] Initial relief efforts included TEMA opening shelters in Waverly, Dickson, and Centerville to house displaced families.

[30] Many groups and organizations came to the aid of residents, such as the Red Cross, which assisted in TEMA and local partners in setting up shelters and bringing in supplies.

[31] The Mount Juliet High School football team donated gear to Waverly Central High School to replace items lost in the flooding,[19] and the Tennessee Titans organization donated $50,000 to flood relief, in addition to offering a new washer and dryer and use of Nissan Stadium to the Waverly football team for homes games during the season.