I shot this on a storm chase from April of '06. We'd driven all the way down to Kansas and waited most of the day for storms to fire, but almost all the action was popping up far south of us in Okalahoma. We kept refreshing the GOES weather satellite image on our laptop, looking for any sign of something nearby trying to develop. With about an hour and a half daylight left, I noticed cumulus clouds beginning to bunch up to our east -- often a sign of instability and storms getting ready to fire. We pack up the equipment, headed down the highway, and this storm literally developed right on top of us. It never put down a tornado, but it put on a spectacular show of lightning and color at sunset. Here, two Oklahoma storm chasers we met up with watch a wall cloud develop nearly overhead.

In the Storm Chaser photo essay.