ELVEs over TS Laura
© Frankie Lucena
Above: The red arrow points from Lucena's camera to the approaching storm
Last night, Frankie Lucena of Puerto Rico trained his cameras on the eastern sky, anticipating the approach of Tropical Storm Laura. He recorded something he didn't expect. "The storm was generating ELVEs," he says. Note the flashing donut of light just above the treetops in this animation:


"In total, I recorded 3 flashes of ELVE lightning between the trees and Mars," he says. "You can see them all in this video."

First seen by cameras on the space shuttle in 1990, ELVEs (Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources) appear when a pulse of electromagnetic radiation from cloud-to-ground lightning propagates up toward space and hits the base of Earth's ionosphere. A faint ring of deep-red light marks the broad 'spot' where the EMP hits.

The fact that ELVEs are appearing above Laura means that the tropical storm contains some fierce lightning. For ELVEs to appear, the underlying lightning needs to be very strong--typically 150-350 kilo-ampères. For comparison, normal cloud-to-ground flashes only reach 10-30 kA.

"Mars is very bright in the night sky now and was located just above these three events--a very fortunate coincidence," says Lucena. "Now it looks like I'm going to have to hunker down and hope Laura doesn't take down my remaining avocado, banana and bread fruit trees."

Learn more about the history and physics of ELVEs here and here.