Weather radar signature was military ‘chaff,’ not grasshoppers, National Weather Service clarifies

Military chaff — a reflective substance designed to confuse radars — is likely what radar imaging picked up last month, an expert says.

(National Weather Service, Salt Lake City) Radar from the National Weather Service at around 6 p.m. on June 21, 2023. Scientists initially said the swarm-like shape moving over the West Desert was a group of grasshoppers, but further investigation showed the source was likely military chaff, a meteorologist said Saturday, July 8, 2023.

The National Weather Service said Saturday it wasn’t a large swarm of grasshoppers its radar imaging caught moving into northwest Utah after all.

A week after announcing that alarming discovery, the weather service reported that further analysis showed that the unusual blip on the radar most likely was caused by material released from a U.S. Air Force base in Nevada.

Scientists initially identified the June 21 radar movement as insects, because the group was very “non-uniform,” and meteorological events — like raindrops and snowflakes — tend to be more consistent in shape, meteorologist Alex DeSmet said.

However, meteorologist Monica Traphagan said Saturday that further analysis identified the radar movement as “chaff,” a reflective substance deployed by the military to confuse radars — such as those that guide missiles. This chaff, Traphagan said, originated from Nellis Air Force Base, about 10 miles northeast of Las Vegas.

“It can sometimes confuse our radars as well,” Trapahagan wrote in an email Saturday. “The appearance of insects and chaff can have some similar characteristics, which led to the error in the original analysis.”

The idea that a swarm of grasshoppers would be spotted in the Utah desert isn’t that far-fetched. The northeastern Nevada city of Elko recently dealt with a Mormon cricket invasion, with millions of the blood-red insects blanketing parts of the city, The Associated Press reported June 20 — a day before the weather service first noticed the unusual radar movement.

Managing pests — when they do occur

Utah has a long history with grasshoppers, and the insects reproduce cyclically. They have “bust” and “boom” cycles every six to eight years, and sometimes the populations will be “infestation type levels,” State Entomologist Kris Watson said.

“We should always be vigilant as producers in the agriculture industry ... assuring that we don’t have grasshoppers in there early,” Watson said. “Not just kill the grasshoppers. We’re looking to help manage the problem so that we don’t have ongoing populations for years and years to come.”

This year’s most popular hopper is the clear-winged grasshopper, Watson said, but the only unique thing about this year’s insect population is its delayed emergence, due to the cooler spring the state experienced. This means much of the state’s bug population is about three weeks behind its typical population growth.

“They can be a nuisance pest — any insect,” Watson said, “it doesn’t matter what it is, if it’s in numbers, people aren’t going to like it.”

Salt Lake City’s mosquito population, for instance, is skyrocketing after the state’s wet winter and spring, which made for more standing water, where the biting insects breed, according to an official with the Salt Lake City Mosquito Abatement District.

A nuisance pest is not the same as rangeland pests, which have the potential to devastate fields and crops, Watson said, “all the way down to a loss of their production.”

Watson is more concerned about invasive pests — like the emerald ash borer, Japanese beetle and spongy moth.

“Those are our some of our largest trapping programs or monitoring programs — invasive pests that we don’t have here, we don’t want here,” Watson said. “Early detection of those pests is crucial in being able to do the best management possible and potentially keep them from establishing in the great state of Utah.”