London (CNN) On one day every year, as per tradition, Britain is invaded by swarms of flying ants -- and this year, the insects arrived in such vast numbers they were seen from space.

The insects swept into the south of England on Tuesday, in an invasion that -- at first glance -- seems to indicate we are living in the early stages of a disaster movie.

So huge were the storms that weather radar mistook them for rain -- a far more common phenomena on the British Isles.

BBC Weather presenter and meteorologist Simon King noticed the error, writing on Twitter alongside a video of the radar readings: "Flying ants!!! Swarms of them flying into the sky in S Eng are being picked up as rain on the radar image this morning...!"

Flying ants!!!



Swarms of them flying into the sky in S Eng are being picked up as rain on the radar image this morning...!#flyingantday #flyingants 🐜🐜🐜🐜#yuk pic.twitter.com/QGOcikqJFq — Simon King (@SimonOKing) July 17, 2019

But while the attack may seem unusual, it merely signaled the annual arrival of what has come to be known as Flying Ant Day.

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