...by the nuclear rainfall.
So, kind of a good news/bad news.
There's been a gentle rain all day today; the authorities say that there's no danger of measurable radioactivity in the rainfall. (Let's hope they're not speaking precipitously.) There really isn't much radioactivity in the atmosphere despite the nuclear incident in Japan, and anyway the prevailing wind is from the west, away from Korea.
But Koreans can be kind of paranoid. (The students in cross country told me they don't run in a drizzle because Seoul's acid rain makes people's hair fall out. Also, people believe that sleeping in a closed room with a fan on can kill you, if American beef doesn't. And so on...)