But if you look at the cover of our November issue, you won't see that storm. You'll see Samaras and a funnel that tore through Manchester, South Dakota, in 2003. The event was featured in our April 2004 article "Chasing Tornadoes," which detailed how Samaras, an electrical engineer and National Geographic grantee, designed and deployed pioneering "turtle" probes in the path of tornadoes.

On June 24, 2003, one of Samaras's probes measured a record drop in pressure—the condition that triggers a twister's extreme wind speeds—inside a 200-mile-an-hour wedge tornado.

"This information is especially crucial," Samaras explained in 2004, "because it provides data about the lowest ten meters of a tornado, where houses, vehicles, and people are." That "helps us understand