Something unexplainable appeared on the weather radar on Dec. 10 in Kentucky.
Around 2:50 p.m. on Dec. 10, the crews at the National Weather Service office in Paducah saw something peculiar in the Southern Illinois region.
Color-coded from blue to red, the radar image seemed to suggest a strong storm surrounded by clear-blue sky. Imagine this: you are looking out of your window and find that while there’s not a drop of rain in your garden, your neighbors’ garden is raining cats and dogs.
The clear sky was correctly reflecting the actual weather situation—a mild day with light winds and temperature in the 20s.
As shown in the 6.5 hour time loop recording posted by NWS Paducah’s Twitter account, the unexplainable stretch of colors originated in far southern Richland County, Illinois, in a rounded shape and moved southwards towards western Kentucky as it elongated.
The leading theory is chaff that originated in far southern Richland County IL around 2:50 PM this afternoon. Here is a 6.5 hour loop…. pic.twitter.com/eVwEbLVsQ7
— NWS Paducah (@NWSPaducah) December 11, 2018
About half an hour earlier, the NWS Paducah published a post saying that they were sure that it was not a matter of perception, and asked people in the area to look for anything overhead or falling.
The NWS Paducah’s posts about the strange radar pattern received various responses from Twitter users; while some expressed their surprise and confusion, others gave various theories—from aliens, Santa, meteorite, a flock of birds and chaff.
A flock of birds may sound reasonable to some but NWS Cleveland explained in a tweet that it was unlikely for birds to be flying at 9000 feet in the sky.
Chaff is a type of military decoy used to fool radars and is made of small fibers which can reflect radar signals, according to globalsecurity.org. The NWS Paducah said that chaff was their leading theory.
“Upper level winds can be much stronger this time of year. However, winds aloft late Monday averaged 10 to 15 mph from the north northwest. That would explain the rather slow movement and slow dispersion of the chaff debris,” wrote NWS Paducah in a post.
The NWS Paducah also posted a link of a pdf document about chaff shown as radar echo two years ago in Alabama.
Upper level winds can be much stronger this time of year. However, winds aloft late Monday averaged 10 to 15 mph from the north northwest. That would explain the rather slow movement and slow dispersion of the chaff debris.
— NWS Paducah (@NWSPaducah) December 11, 2018
However, even the most likely explanation was questioned.
“Pretty crazy to have a chaff stream in the air this long and an area this big. Makes me think this is something different,” wrote Chris Conley in a Twitter response.
Pretty crazy to have a chaff stream in the air this long and an area this big. Makes me think this is something different. pic.twitter.com/ZAzUs5QAFN
— Chris Conley (@MeanMotionMedia) December 11, 2018
The pattern eventually grew thinner and almost disappeared from the map after ten hours. However, it wasn’t until around midday of Dec. 11, when a post by Wayne Hart, Chief Meteorologist for Eyewitness News WEHT Local, was published, that the mystery was cleared.
“Information from a pilot appears to confirm that chaff was the mysterious radar echo that traversed #tristatewx late Monday afternoon/evening. Pilot was told by EVV Air Traffic Control that chaff was released by a military C130 northwest of Evansville,” wrote Wayne Hart in a tweet.
Information from a pilot appears to confirm that chaff was the mysterious radar echo that traversed #tristatewx late Monday afternoon/evening. Pilot was told by EVV Air Traffic Control that chaff was released by a military C130 northwest of Evansville. @NWSPaducah
— Wayne Hart (@Wayne_C_Hart) December 11, 2018
Wayne Hart added that the chaff was from a military exercise in a later response.
Despite the confirmation, several Twitter users continued to question the real reason behind the formation of the radar echo.
Their questions were not entirely baseless. Greg Meffert, a meteorologist from the NWS, told Courier and Express that it was their first-time seeing chaff showing this strong on a map.
Moreover, according the Drive, despite the location being a military operation area (MOA) and its airspace used for military aircraft training, for a C-130 aircraft to release chaff at a relatively low altitude at that specific location was also out of ordinary.
