In the evening hours of April 3, 1974, a series of two large and destructive tornadoes would impact Tanner, located in the state of Alabama.

Each of the tornadoes claimed over fifteen lives, and would kill a combined total of fifty-five people, many in the Tanner area; over four hundred more would be injured.

The tornado would continue to produce extreme damage as it moved to the northeast, ripping water pumps out of the ground and obliterating large objects.

Based upon real-time satellite imagery and model data, differential positive vorticity advection coincided with the left exit region of an upper-level jet streak which reached wind speeds of up to 130 kn (150 mph) (66.9 m/s (241 km/h)), thereby enhancing thunderstorm growth.

These storms, forming after 23:00 UTC, produced some of the most powerful tornadoes of the outbreak, including a large and long-tracked F4 that struck the western and central portions of Alabama, tracking for just over 110 miles (180 km), two F5s that both slammed into Tanner, causing extensive fatalities, an extremely potent F5 that devastated Guin in Alabama, and multiple violent, deadly tornadoes that affected and caused fatalities in Tennessee.

[4] In one case, the destruction was so complete that a witness reported that the largest recognizable objects among scattered debris from an obliterated house were some bed-springs.

[5] The tornado crossed into Morgan County, causing additional destruction in rural areas near Hillsboro and Trinity.

[6][7] Crossing the Tennessee River into Limestone County as a large waterspout, the tornado flattened a ¾-mile–wide swath of trees on the opposite bank.

[3] The storm then slammed into Tanner, where many homes were swept away, vehicles were tossed, shrubbery was debarked, and Lawson's Trailer Park sustained major damage.

Numerous homes in Harvest and surrounding rural areas of the county were swept completely away and scattered, and extensive wind-rowing of debris was noted.

While rescue efforts were underway to look for people under the destroyed structures, few were aware that another violent tornado would strike the area.