When conditions align perfectly, disaster comes rushing across the Great Plains: A supercell storm, made distinct with its wide, anvil-shaped formation at its top, can unleash hail, lightning and tornadoes. In short, a supercell on the horizon is an ominous sign. A tornadic supercell storm moving over the Great Plains during sunset. A supercell moving over the Great Plains. The weather events were seen as a threat to flights—so naturally, the project flew planes directly through storm clouds.