April 17, 2015 10:19 AM EDT

Forget cats and dogs. It’s been raining worms in Norway.

Biology teacher Karstein Erstad recently came across “thousands of earthworms” on top of snow at least half a yard deep while skiing on mountains outside Bergen, according to The Local, an English-language European news network.

“It’s a very rare phenomenon,” he said, citing reports he found of worm rainfall in the 1920s. “It’s difficult to say how many times it happens, but it has only been reported a very few times.”

“People have now observed the same phenomenon in many places in Norway,” added Erstad. “It’s very peculiar, I don’t know why so many people have discovered it. I don’t know if there have been some special weather conditions lately.”

[The Local]

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