It's Wales... If it stops raining for more than 24 hours, they get a bit excitable, overdose on nuggets and Pringles and away to go. I don't think that stopping them from singing Delilah has calmed them down much.
150 is a pretty shit "riot" by anyone's measure; they should send some of them on a fact-finding mission to France, where they know how to kick off properly (and their plod know how to deal with it).
Chucking coal at the neighbour's cars is probably the only use for it these days.