I mean, I know. My uncle was nuked (sort of on purpose) several times. When he was a teenager in Las Vegas in the 1950s, he and his buddies would go out to drink beers in the desert and watch the bombs go off. He said the ash would fall around them like snow. By the time he was 24 his hair was shock white and he was sterile. Oddly enough, he looks exactly the same jolly guy now as he did my whole life, like Santa Claus, and is still playing golf and fishing at 82 years old.
At the time of the rainstorm in Granada, we were hearing that the spent fuel pools on the roof of the reactors couldn't be kept full of water and were burning off into the atmosphere. I can't find the specific readings from around Europe at that time, but I don't think they were "baseline" 24-years post Chernobyl or even anything closely resembling that. To say that equipment is more sensitive is nice; many places I lived no one would still eat wild boar or certain mushrooms all those years after 1986. It is possible for a rainstorm to concentrate fallout from the upper atmosphere, and it also would be harder to detect than these giant HVAC units pulling in sea-level air.