The first day of a two-part severe thunderstorm event is unfolding across the middle of the country, with an enhanced risk for severe weather—three on a scale from zero to five—possible in Oklahoma, Arkansas, and Missouri. Storms could produce very large hail, damaging winds, and a few tornadoes.

Check out this excellent interactive feature created by Brian Crumpler on the Mayflower/Vilonia, Arkansas EF-4 tornado that touched down on Sunday. The feature blends together radar images, maps, and pictures of the damage to give you an in-depth look at how the tornado evolved along its 40-mile path.

A large, devastating tornado northwest of Little Rock, AR lofted so much debris into the air that the tornado and its parent mesocyclone (broad column of rotation within the storm) were visible on 3-D radar imagery. The debris reached over 12,000 feet high as the up-to-a-mile-wide tornado tore a path through central Arkansas extending dozens of miles.