Memorial stone commemorating the people injured and kille during a tornado in Spencer, South Dakota, USA. The Center for Severe Weather Research team visited the town. They were there when the tornado hit it in 1998. The CSWR is a nonprofit research organisation based in Colorado, USA. This trip was one of many the crew has made on its 2004 Radar Observations of Tornadoes and Thunderstorms Experiment that started in late March. The project seeks to better understand tornadoes in order to speed up the alert process.