Hurricane Nicole Caused Rare Sprite Lightning Before Storm Hit Florida

As Hurricane Nicole pummeled toward the Florida coast on November 8, photographers in Puerto Rico saw a strange and rare sight in the storm clouds, known as sprite lightning.

"This sprite appeared over one of the outer bands that was generating lots of lightning," Frankie Lucena, a photographer based in Puerto Rico, told SpaceWeather.com. "By the way, the outer bands [of the storm] are the best places to look for sprites. Back in 2016, I captured a bunch of sprites in one of the outer bands of Hurricane Matthew."

"Sprites are large-scale, lightning-like discharges that happen above thunderstorms," Caitano L. da Silva, a physics professor at New Mexico Tech, told Newsweek.

Sprites occur at heights of about 50 miles up into the atmosphere.

"They happen in response to powerful cloud-to-ground (CG) flashes in the underlying thunderstorms. These CG flashes radiate a strong electric field that creates sprites at the edge of the lower ionosphere, aka the edge of space," da Silva said. "Sprites are brief, but are huge, 50 km [30 miles] tall by 50 km [30 miles] across, about the size of a small town."

The reason that sprites appear in these strange, jellyfish-like patterns is because of a unique combination of altitude, cloud electrical charge and temperatures.

"Note that this altitude range is actually the coldest region of the atmosphere with temperatures down to -120 degrees Celsius (-180 degrees Fahrenheit). In these harsh and vertically rather uneven conditions, the developing electric discharge behaves differently at different altitudes so that eventually a figure like this is formed," József Bór, a lightning researcher at the Institute of Earth Physics and Space Science (ELKH EPSS) in Hungary, told Newsweek.

"Red sprites can be thought of as a secondary lightning that follows conventional, but very intense lightning strokes which can be considered as the parent lightning of the subsequently appearing red sprite," he said.

When the "parent" lightning discharge moves a very large amount of electric charge from the cloud to the ground, an excess amount of electric charge of the opposite charge remains in the upper part of the thundercloud, Bór explained.

For a short time right after the parent lightning stroke occurs, the electric field of the excess electric charge in the cloud can be strong enough to allow a secondary electric discharge to form in the very low pressure region of the atmosphere high above the clouds.

"When this condition is fulfilled for a fraction of a second, the electric discharge actually forms and it can produce a red sprite-type optical emission. Note that there are a great variety of the shapes red sprite may take on either because the parent lighting strokes are different and they leave (or deposit) the excess amount of electrical charge in different configurations in the cloud, but also because the electric field above the cloud may last a bit longer or shorter and it can also vary differently during the time period when it is strong enough to produce sprites," Bór said.

The red color of the sprites comes from nitrogen molecules in the atmosphere being excited by the discharge from thunderclouds, according to the University of Washington's Department of Earth and Space Sciences. They can also come in a variety of forms, ranging from the larger Jellyfish sprites to Column sprites, and Carrot sprites, which are more elongated. Carrot sprites have long, dangling tendrils above and below, with the lower tendrils tending to be blue in color.

Red sprites are so rare because the very strong lightning strikes capable of producing them don't occur very often. In this case, the burgeoning Hurricane Nicole was able to generate enough electrical charge.

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