On May 31, 2007, I was storm chasing with my friends with Cloud 9 Tours. We followed several cells in a line of storms from southwest of Elkhart, KS to east of Guymon, OK. One of these cells had a persistent funnel that tried to touch down several times but never quite managed it. There was tremendous updraft and cloud rotation most of the time during the chase, which lasted over four hours. Late in the chase, the cell of interest morphed into this mushroom. The cell was so massive that I was forced to take two shots and then stitch them together to produce this photo. It was subsequently published in the August, 2008 issue of National Geographic Magazine.