©2006, 2004 WGBH Educational Foundation. All rights reserved.

Adapted from NOVA "Hunt for the Supertwister". A NOVA Production by Thomas Lucas Productions, Inc. for WGBH/Boston. Stock footage courtesy of Channel 9 KWTV, NOAA, and Roger Hill. Animation courtesy of NCSA 3D Storm Simulations. Radar images courtesy of Joshua Wurman and ©Howard B. Bluestein/University of Oklahoma.