Red sprites are a high-altitude extremely rapid lightning discharge that happens over thunderstorms. According to a recent National Geographic post, “sometimes called “upward lightning” and “cloud-to-stratospheric lightning,” sprites are momentary bursts of electricity that can literally reach the edge of space, about 50 miles above the ground. They’re rarely documented because they are so short lived (typically about 10 milliseconds) and are often obscured by clouds. In fact, evidence of sprites is so rare, the phenomenon was thought to be a myth until it was photographed by a pilot in 1989.”
National Geographic has a Weather Channel video explaining the sprites and showing some spectacular images of red sprites that were recently photographed over Hurricane Matthew. You can see it at https://news.nationalgeographic.com/2016/10/lightning-sprites-form-over-hurricane-matthew/?google_editors_picks=true.
