Alot of the people tweeting wanted info because they were concerned about relatives in different parts of the UK so local radio isn't gonna be useful for someone in Manchester concerned about whats going on in Norfolk.
They could have listened in to the BBC local radio station in the affected area online. They are all available.
I don't buy that BBC1's national news HAD to cover the floods, especially since the Mandela story had broken just minutes before, and was quite obviously the major international story. The weather was not even the top national story at that point, it was second to the Autumn Statement., and both stories got bumped, in fact every other story got bumped. I think that realisation is lost in the kerfuffle over the floods story getting bumped, it wasn't the only story to get bumped off the Ten, it wasn't even the biggest story to get bumped off the Ten.
Local radio was the place to go to get that information, not BBC1's national news. BBC Radio Lincolnshire and many other stations up and down the east coast, was the place to get that, and it was available to listen to online. To expect the national news on BBC1 to cover that, when the Mandela story was that fresh, is not realistic.
Now, on any other night, I'd have been calling for extended regional news programming on BBC1 regions where the floods would be the major story, but quite honestly, I don't think it would have been editorially correct to have some regions covering their own floods situation, at the same time the rest of BBC1 would have been covering the Mandela story. You can argue that with BBC News showing the Mandela story, there would have been a choice, that's not an insignificant argument either, but at the end of the day, in editorial terms, BBC1 is primarily a national channel, with regional opt-outs. yes it is now the only BBC channel to have regional opt-outs and I consider that a mistake, but still, a major breaking international news story is always going to crowd out every other story. Did ITV News at Ten cover any other story other than Mandela? Now, if they had, then you might have an argument, but AIUI they went with Mandela the whole way too, so this argument that the BBC were somehow wrong not to cover the floods, actually belies the reality that neither did ITV in their News at Ten.