Summer Lightning Near Keota, Colorado

September 07, 2010

Ketoa lightning
Photographer: Robert Arn
Summary Authors: Robert Arn; Jim Foster

September 2010 Earth Science Picture of the Day Viewer's ChoiceThe Pawnee National Grasslands in Colorado is an exceptional place both to observe nature and to stargaze. Observers have a nearly unobstructed view of the horizon. During the summer months, lightning can be seen miles away, and the night sky is generally free of annoying light pollution.

While waiting for skies to darken at a star party near Keota, Colorado last month, I directed my scope and camera toward a summer thunderstorm plowing across the plains. Its accompanying lightning; especially the cloud-to-ground lightning was quite dramatic. As shown above in a time-lapse photo, a dozen or more strokes were recorded in less than half a minute. Each bolt typically generates 100,000,000 volts of electricity, and the more energetic strikes can reach temperatures of 54,000 degrees F (30,000 C). Before too long, the storm moved off, and I was able to turn my attention to the clearing and darkening sky. Photo taken on August 6, 2010.

Photo Details: Camera: Canon EOS DIGITAL REBEL XSi (Hap Griffin modified); Lens: EF50mm f/1.4 USM; Focal Length: 50mm; Aperture: f/22.0; Exposure Time: 20.000 s; ISO equiv: 200; Photoshop processing.