Lightning Triggered by TV Antennas and Wind Turbines

March 19, 2020, is a day that would make Jim Cantore of the Weather Channel excited. While a significant winter storm was occurring across Colorado, US, bringing heavy snow and blizzard conditions, portions of the state were treated to thundersnow – when lightning occurs while it is snowing. Typically, when thundersnow occurs, there are only a few flashes of lightning, but that wasn’t the case today.

In just over two hours, Vaisala’s National Lightning Detection Network detected 354 in-cloud and cloud-to-ground lightning events across the Eastern Colorado Plains!

Figure 1: Map showing NLDN detected lightning events in Northeastern Colorado on March 19, 2020.

Why did so much thundersnow occur?

Well, if you read the title of this blog, you’ll know that we already gave you the answer: lightning was triggered by tall TV and radio station transmitter antennas and wind turbines. Our first clue relating lightning to towers and wind turbines is that the events are tightly clustered. In more natural thunderstorms, lightning is more widespread. The high concentration in small locations suggested to our scientists that this was not naturally produced lightning.

Figure 2: Map showing 260 of the 354 detected lightning events occurring near one of the TV transmitter antennas.

How is lightning triggered by towers and turbines?

During winter storms, the base of the cloud is usually fairly close to the ground. TV and radio transmitter antennas and wind turbines can extend several hundred meters or higher above the ground, putting them near the base of the clouds that pass overhead. If there is electric charge in the cloud that passes over a tall antenna or turbine, the lightning development process is made more efficient since the cloud base and the top of the antenna or turbine are close together. The March 19, 2020, event is noteworthy because of the amount of lightning that occurred.

Vaisala’s engineers and scientists will be reviewing this event in detail because lightning events from TV antenna or other tall towers can help us validate the performance of our network. We will also be examining the overall weather pattern of the winter storm to try and understand why so much lightning is produced, to help the owners of tall antennas, wind turbines, and towers understand how lightning can affect their assets.