During the summer, the U.S. Great Plains routinely experiences nighttime thunderstorms unlike anywhere else in the country. These large-scale storms—sometimes spanning entire states—account for more than 40 percent of annual rainfall in some areas. They can bring much-needed rain to farms and help recharge aquifers, but extremely severe events can also destroy fields, homes, and lives. Scientists have been studying the region for decades to learn the underpinnings of this distinct, repetitive weather pattern.