Tornado outbreak of May 26–31, 2013
A prolonged and widespread tornado outbreak affected a large portion of the United States in the final days of May 2013. The outbreak was the result of a slow-moving but powerful storm system that produced several strong tornadoes across the Great Plains states, especially in Kansas and Oklahoma.
Source: Wikipedia — Tornado outbreak of May 26–31, 2013 (CC BY-SA 4.0)