"It's raining worms"

It's the sort of event one would expect to read about in Fortean Times (which is online, BTW, but hasn't found the story yet).  I read about it at a Scottish TV station's website (via Arbroath, of course):

Pupils at a Scots school had to run for cover when it started raining worms during their PE lesson. Teacher David Crichton was leading a group of pupils playing football on an astroturf pitch at Galashiels Academy when dozens of the slimy creatures began plummeting from the sky.

David said the children had just completed their warm up when they began to hear "soft thudding" on the ground. The class then looked to the cloudless sky and saw worms falling on to them..."Then they just kept coming down. The kids were laughing but some were covering their heads and others were running for cover for a while. They just scattered to get out of the way."..

"I spoke with the science department here but none of them had any explanation for it. One of them thought maybe it was a freak weather thing. But it was such a clear, calm day. And we are quite a bit away from any of the buildings so it's not like anyone could have been throwing them.”..

Showers of worms falling from the heavens have been reported in the past. In 1872 worms were reported falling in Somerville, Massachusetts, in 1877 in Christiana, Norway, and in 1924 in Halmstad, Sweden. More recently, in July 2007, a woman was crossing a road in Jennings, Louisiana, on her way to work when large clumps of tangled worms dropped down from above. That incident is believed to have been caused by freak weather over a nearby river lifting water and worms and dumping it over the road.

Plenty of witnesses, and the Astroturf precludes mistaking worms emerging from the ground.  Depending on the geography, the worms still could have been catapulted or sling-shotted from a distance as a prank.  But it does seem likely that a whirlwind lifted the worms from the ground and carried them away.  I wonder what happens to all the other debris that would have been pulled up; do whirlwinds and turbulence sort things by weight as a sort of giant centrifuge?