Officially, and they were not designed to act against ICBM, so even if it's true, it has little to do with the current threat...
Yeah, THAAD was apparently designed to take down short, medium, and intermediate range ballistic missiles, though Lockheed Martin are totes confident in it's anti-ICBM abilities. And you know you can always Lockheed Martin..... Ehh.
Blimey - are these a hangover from WW2? I mean we used to have these in the UK but I presume they're all gone now?
Up in Huddersfield we still test them once a month I think. Toned down volume, but send a chill down my spine whenever I hear them.
Edit: Gonna move this edit down here, it's interesting I think.
BBC Coverage
TLDR
The 'BBC guy with the cute family' (Professor of Political Science at Busan National University) says that NK is emboldened due to being a nuclear power, nobody wants to formally acknowledge it but there's nothing we can do about their new found power. Some sort of reaction to the US/SK military drills is always expected and they know that they won't be punished due to their new position [I assume he's referring to the launch over Japan]. He thinks that the nuclear program would be much further along if we didn't have sanctions in place, and that we should push those more. But that there isn't a huge amount of options for us.
He framed the launch as a way to terrorise Japanese civilians. He suggests that there will be a pressure for a THAAD installation in Japan. And that there will be an arms race between missile development in NK and missile defense with US allies.
Also that there is essentially no chance of a political route to NK reducing their nuclear armaments, though maybe there could be some small concessions.
My personal input, that tweet was right, we're looking at the new norm. Get used to these threads.