Residents of the Illinois–Indiana–Kentucky tri-state area were treated to a genuine airborne mystery this week when weather radar picked up a strange anomaly, puzzling meteorologists and weather watchers alike. Despite the fact that skies were clear and no storms were reported in the area, several weather stations reported a massive, extremely severe-looking storm on their radar systems. While an official explanation was given in the wake of the incident, we all know how official explanations go. What exactly happened in the skies over Indiana this week?
It all began late on the evening of Monday, December 12 when the National Weather Service office in Paducah, Kentucky reported a large anomaly over Southern Illinois which drifted across Southern Indiana and Western Kentucky. Whatever was on radar appeared to be as dense as a thunderstorm, but with the night clear and temperatures low, that theory was ruled improbable.
With little else to go on, National Weather Service believe the only other explanation is chaff released by a military aircraft. Chaff is a common countermeasure designed to fool radar and consists of small fibers or strands of metallized glass, paper, plastic, or aluminum. Clouds of lightweight chaff released by aircraft float on the air and are commonly picked up by weather radar.
However, this recent case appears different. National Weather Service meteorologist Greg Meffert says whatever caused this radar anomaly appeared to track as high as 10,000 feet but also at ground level. If it was chaff, Meffert adds, the weather service has “never seen it quite this hot.” Meffert went on to point out that he’s never before seen the Air Force conduct chaff exercises or tests in the Evansville, Indiana area.
Furthermore, whenever nearby air bases have conducted drills with chaff, residents in the area have found the fibers strewn throughout their yards. In this case, no fibers were reported. Still, several news outlets report that air traffic control in Evansville were aware of a C-130 releasing chaff in the area on Monday. If this was chaff, why did it appear so different from prior tests? It could merely be a new type of countermeasure the weather service is unfamiliar with.
Military aviation blog The Drive adds that chaff does not usually stay in such a tight pattern for over 10 hours like this radar anomaly did. The Drive‘s Tyler Rogoway reached out to all nearby Armed Forces bases to see which might have conducted the chaff test, but none claimed responsibility. Rogoway’s theory is that this was likely “a test involving a more exotic type of material that hangs in the air longer” than normal chaff. Why conduct a test in such an usual location over suburban Indiana and not on a test range, though?