SIOUX FALLS, S.D. (KELO) — Rain and thunderstorms move in one direction in the lifecycle of the system. And sometimes the storms will start moving over the same area. This is called training.
Areas with training can experience excessive rainfall in a short period of time that could turn into flash flooding events.

We have seen several training events in KELOLAND. One training event took place in southeastern KELOLAND on August 21, 2017, the day of the solar eclipse. Between 11:30 a.m. to 4 p.m., southeastern Sioux Falls received 6 inches of rain.

Excessive rainfall and flash flooding is more impactful in cities where there is less soil to absorb the rain. City storm systems can also get overwhelmed during extended storms.

This is what happened on Friday with the severe weather. The tornadoes took all the energy in Nebraska and moved north. As the storms were moving, they were moving over the same areas which used all the energy quickly and led to heavy rainfall in southeastern South Dakota.