Scientists Capture Rare Ultraviolet Coronae on Trees During Thunderstorms

Researchers document the first real-world evidence of the faint electrical discharges lighting up treetops.

Published on Feb. 25, 2026

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A team of researchers from Pennsylvania State University have captured the first documented evidence of coronae - brief, colorful electrical discharges - lighting up the tips of leaves on trees during thunderstorms. After decades of speculation, the scientists recorded 41 coronae on a sweetgum tree in North Carolina, with the glows hopping from one leaf to the next over a 90-minute period.

Why it matters

The discovery of coronae in the wild confirms a long-held scientific theory about the electrical activity that can occur in trees during thunderstorms. While the faint discharges are not visible to the naked eye, the study suggests they may be far more common than previously thought, potentially lighting up tens to hundreds of leaves on treetops during any given storm.

The details

To capture the coronae, the researchers outfitted a Toyota Sienna minivan with specialized equipment including a weather station, electric field detector, laser rangefinder, and an ultraviolet camera connected to a roof-mounted periscope. During a thunderstorm in Pembroke, North Carolina, the team recorded 41 coronae on a sweetgum tree over 90 minutes, with each glow lasting around 3 seconds and often hopping between leaves. The team chased several other storms from Florida to Pennsylvania, detecting similar electrical discharges on loblolly pines and other tree species.

  • In the summer of 2024, the researchers went storm-chasing in North Carolina.
  • On February 25, 2026, the study was published in the Geophysical Research Letters.

The players

Patrick McFarland

A meteorologist at Pennsylvania State University and the lead author of the study.

Pennsylvania State University

The university where the research team is based and where the study was conducted.

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What they’re saying

“These things actually happen; we've seen them; we know they exist now. To finally have concrete evidence [of] that...is what I think is the most fun.”

— Patrick McFarland, Meteorologist (Geophysical Research Letters)

“If we were able to see it, 'it'd probably look like a pretty cool light show, as if thousands of UV-flashing fireflies descended on the treetops.”

— Patrick McFarland, Meteorologist (Geophysical Research Letters)

What’s next

The researchers plan to continue studying coronae in the wild, exploring how the electrical discharges may impact tree health and behavior during thunderstorms.

The takeaway

The discovery of coronae on trees during thunderstorms represents a significant scientific breakthrough, confirming a long-held theory about the electrical activity that can occur in nature. While the faint discharges are invisible to the naked eye, the study suggests they may be far more common than previously thought, potentially providing a new window into the complex interactions between trees and the atmosphere.