More than 1,200 tornadoes rip through the U.S. Midwest in an average year, killing about 100 people and costing millions of dollars in damage. Currently the longest warning time meteorologists can give is a nerve-racking 13 minutes, with a 70 percent false alarm rate.

Scientists aim to improve this. On May 1, an armada of more than 100 scientists driving 40 trucks will cross the Great Plains on the hunt for twisters. The two-year project called VORTEX2 is the largest field experiment in history. With more than $10 million in funding from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA), researchers from more than a dozen universities and several government and private organizations hope to learn more about the formation, structure and evolution of tornadoes.

Scientific American caught up with VORTEX2 in the field last May. In this exclusive video we find out what scientists still don't know but could soon figure out about one of nature's most violent and unpredictable forces.