A massive "bloom" of ladybugs appeared as a weather pattern on the radar screens of the National Weather Service's San Diego bureau on Tuesday night, and it took them a minute to figure out what it was.
There were no clouds in the sky over the San Gabriel Mountains when this huge green "echo" took over the radar, in the vicinity of the town of Wrightwood, California. As NBC News reports, it took some calls to weather spotters in the area before forecasters understood that this was just a particularly large instance of an annual bloom of flying beetles in the family Coccinellidae, also known as ladybugs.
The swarm was estimated to be about 80 miles in diameter, and was flying between 3,000 and 5,000 feet. "I don’t think they’re dense like a cloud," NWS meteorologist Joe Dandrea told the LA Times. "The observer there said you could see little specks flying by."
Were it not for an improvement in technology, the ladybug swarm might not have shown up on the radar at all. As NBC News notes:
About 10 years ago, [the NWS] upgraded the system with what it calls Super Resolution, which allows vastly more detailed imagery. The imagery is so detailed, in fact, that it frequently picks up so-called non-weather targets like the ladybug swarm on Tuesday.
The radar systems have been known to pick up everything from migrating birds, to butterflies, to bats.
Though the size of the bloom might be unusual, the occurrence itself isn't in that part of California. Lady beetles typically migrate down from the Sierra Nevada in early spring into the valleys in order to eat aphids and mate. Then in early summer they begin moving to higher elevations for food.