Volcano Eruption LightningApril 14, 2009--Lightning, which often accompanies large eruptions, illuminates a giant ash cloud from Alaska's Redoubt Volcano, southwest of Anchorage, in a March 28 picture by an amateur astronomer. (See daytime pictures of the Redoubt Volcano eruption.)

To "see" the lightning inside volcanic plumes, scientists began setting up four lightning mapping arrays, which look like large antennas, near Redoubt Volcano in January. Often used to predict thunderstorms, such arrays had never before been deployed before an eruption.

"We don't always get lightning [when a volcano erupts]," said Steve McNutt, research professor of volcano seismology at the University of Alaska, Fairbanks, who was involved in the project. "And that's one of the things we're trying to figure out."

Photograph courtesy Bretwood Higman