This article was first published in the September 2015 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online

This dramatic flash is a lightning storm raging at the top of a volcano. The light show, observed at the peak of the Calbuco volcano in Chile in April 2015, is a phenomenon known as volcanic lightning. In a recent Geology paper, co-author Steve McNutt, a volcanologist at the University of South Florida, explained that this happens when particles of ash and lava shoot out of the crater and rub together, generating bursts of static electricity. "Inside the flash, the temperature can reach up to 30,000°C, and it can melt ash and rock particles," McNutt says.

Volcanic lightning has only recently started to be researched. Although it is independent of other weather conditions, there are similarities to thunderstorms -- particularly when the volcanic plume is higher than seven kilometres and ice starts to form inside it. "This is referred to as a 'dirty thunderstorm'," McNutt says.

His research also found that volcanic lightning can leave behind a trail of glassy spheres measuring about 50 microns in diameter. Scientists can use them as an evolutionary chemical "signature", which could help to better understand previous volcanic activity. Get ready to flashback.

This article was originally published by WIRED UK