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Cicadas cause unusual disruptions, but experts say the swarms aren't a major concern

The billions of Brood X cicadas swarming across the East and parts of the Midwest have caused several unusual disruptions over the past week.

The billions of Brood X cicadas swarming across the East and parts of the Midwest have caused several unusual disruptions over the past week, including the grounding of a White House press plane, a car crash in Ohio and even an appearance on weather radar. But apart from some scattered examples of cicadas' wreaking havoc, the country isn't seeing widespread slowdowns due to the mating insects, experts said.

Journalists set to cover President Joe Biden's first trip abroad were delayed by six hours after their charter plane at Dulles International Airport suffered mechanical problems Tuesday caused by cicadas.

Delta Air Lines said in a statement that the charter flight was delayed Tuesday night because of the "presence of periodical cicadas" in the auxiliary power unit, or small turbine engine, which rendered the engine unworkable. Delta teams dispatched a replacement plane and crew to operate the flight, which left after 3:30 a.m. Wednesday, about six hours late, the statement said.

A spokesperson said the Metropolitan Washington Airports Authority wasn't aware of cicadas' causing delays for any other commercial or charter flights at Dulles.

If such an incident could happen at Dulles, it could happen at other airports, said Kathleen Bangs, a former commercial airline pilot who is a communications strategist for the flight tracking website FlightAware, adding that she still expected the impact of cicadas on travel to be "very minimal."

But insects and other animals have been responsible for major accidents in the past, including the crash of a chartered plane in the Dominican Republic in 1996, which killed nearly 200 people on board after an insect nest blocked a pitot tube, she said.

It's not unheard of for large swarms of insects to cause mechanical problems. In 2010, during a stink bug outbreak that affected several mid-Atlantic states, a farmer in Maryland reported that the invasive insects clogged up part of a soybean harvester, causing it to overheat and catch fire, said Doug Pfeiffer, a fruit entomologist at Virginia Tech.

Image: A cicada shell at the White House
The shell of a Brood X cicada on a tree on the North Lawn of the White House on May 25.Carolyn Kaster / AP

"It's to be expected," Pfeiffer said. "Insects in high enough numbers can definitely cause mechanical issues."

In some cases, it's not necessarily the insects that can cause disruptions but, rather, people's reactions to them.

"Many people are just unduly afraid of insects, so if one flies in the window, they may panic and not pay attention to driving," Pfeiffer said. "There's an emotional overreaction, in addition to some real problems that could crop up when there are insects in very high numbers.

Police in Cincinnati, for instance, said Monday that a cicada flew through an open window and struck a driver in the face, causing the person to crash into a pole.

It's estimated that billions of cicadas will emerge over the course of their monthlong mating ritual. In certain regions, the populations of cicadas have been so large that swarms have shown up — at least in part — on weather radar. Over the weekend, the National Weather Service office in Baltimore and Washington, D.C., tweeted a photo of radar imagery showing the Washington metro area cloaked in what looked like a fuzzy blanket.

"You may have noticed a lot of fuzziness (low reflectivity values) on our radar recently. The Hydrometeor Classification algorithm shows much of it to be Biological in nature. Our guess? It's probably the #cicadas," National Weather Service officials tweeted Saturday.

Chris Strong, a meteorologist with the National Weather Service's office in Baltimore and Washington, said: "It's unusual, certainly, to see low-end reflectivity on our radar from cicadas that are out there. It's been in the background in particular since it really warmed up last week, so it's pretty much an ever-present thing that we can see right now."

And while the insects might "trick the radar" sometimes into indicating that there may be a bit more precipitation than there actually is, overall their effect is "not very impactful," he said.

Kathryn Prociv, a meteorologist for NBC News, said "one of the highest concentrations of where the cicadas are right now happens to be co-located with that radar site."

She said the positioning of the site, combined with factors like the hot and humid atmosphere, could contribute to the cicadas' being picked up by the radar.

"It's like the perfect cicada storm," she said.

Prociv said it was important to note that what showed up on radar wasn't likely to have been all cicadas — it could have included higher-flying insects or the high moisture content in the air, among other things.

Prociv said the cicadas were "totally harmless" to the radar site and its ability to forecast.

"If storms and rain come through, we can obviously pick that up despite the cicada clutter," she said. "They're not going to make us miss a storm on radar."

May Berenbaum, an entomologist at the University of Illinois, was skeptical that cicadas could fly high enough and in sufficiently big clusters to be detectable by radar. Cicadas aren't known to fly great distances the way migrating insects do, and they usually stay relatively close to the ground.

And although cicadas emerge from underground en masse, they don't typically move around in huge packs, Berenbaum said.

"They don't swarm in the same way that bees swarm," she said. "And they're not built for long-distance flight. They just have to get from one tree to another, so they don't usually fly above 500 feet. At that distance, they're literally under the radar."

Gene Kritsky, an entomologist at Mount St. Joseph University in Cincinnati, said it's possible that the stretch of colder, rainy days across much of the Midwest over the Memorial Day weekend drove the cicadas to be more active higher up in tree canopies, where they were seeking shelter from the elements.

"Cicadas tend to take cover from the rain — they'll actually crawl under leaves and on the underside of branches," he said. "But then, when the sun comes out again, they get active and loud pretty fast. And that was a lot of the warming that we had over the weekend."

Kritsky said that because the National Weather Service's radar images overlap with where cicadas have been emerging, it's reasonable to assume the fuzzy patches include Brood X swarms.

While the emergence of billions of insects may be a nightmare scenario for some, cicada researchers are overjoyed at the attention this year's event is getting, particularly compared to 17 years ago, when Brood X cicadas last tunneled up from underground.

"The last time Brood X emerged, we didn't have iPhones," said Kritsky, who released an app in 2019 called Cicada Safari, which allows citizen scientists to report cicada sightings. "Now we're all walking around with small computers in our pockets, and we can share videos and photos and audio. It's really helping us to fill in some of these missing pieces when it comes to the science."