On May 22, a tornadic supercell formed over Minnesota. It caused major damage in and around Minneapolis. A strong tornado also moved towards Harmony that afternoon and a tornado emergency was issued. Late that afternoon, a very large and strong tornado resulted in serious damage in Joplin. Entire communities were destroyed. Many people were reported to have been trapped in destroyed houses. A total of 158 were killed, and more than 1,000 others were injured.