The 2024 Attica-Harper, Kansas tornado was a violent EF4 tornado which impacted extreme southern Kansas in the early morning of Friday, May 31, 2024. Part of the 2024 Super Outbreak, the tornado touched down at 1:26 AM CDT in rural Barber County to the southwest of Attica, tracking almost due east while intensifying explosively. The tornado reached EF4 strength as it struck the town, then continued through rural areas of Barber County and into Harper county at EF2 to low-end EF3 strength, before reaching EF4 strength for a second time to the south of Harper itself. The tornado then dissippated over empty fields in Harper County to the southeast of Harper.
The tornado remained on the ground for 22 minutes over a 19.75 mile path, over which it caused 7 fatalities and 138 injuries. All but one of the fatalities occurred in Attica, where the tornado was estimated to have reached peak strength. Damage in both Attica and Harper was rated low-end EF4, with estimated wind speeds of 170 miles per hour. Damage surveys determined that most of the tornado's victims were determined to either have been killed in their sleep or been woken by the storm too late to reach a safe area. The tornado's forward speed, which exceeded 50 miles per hour along much of its path, contributed to its deadliness despite the fact that no large towns or cities were struck.
The Attica-Harper tornado was compared in both official surveys and in media to the 1984 Barneveld, Wisconsin tornado, as both tornadoes struck in the overnight hours, and were preceded by a power surge which, in the case of the Attica-Harper tornado, caused tornado sirens across both Attica and Harper to remain silent. Notably, the Attica-Harper tornado's parent supercell had produced a long-tracked, EF5-rated tornado which struck Liberal, Kansas hours earlier and caused a death toll of 26.