The BBC and ITV have a system, which is a bit ad hoc, to cope with missing kids don't they?
In terms of things like school closings, that's definitely the province of BBC Local Radio - and everyone knows to tune to it if there is bad weather, and the Breakfast News regional bulletins will include a "For full details of school closures because of the bad weather, check with your BBC Local Radio station".
One thing we could take from US 'local' TV is scrolling captions on network output.
There's no technical reason why the regional BBC centres couldn't have an info ticker on the screen during Breakfast, (and any other time during local emergencies). Rather more difficult for ITV, because of their different network architecture, (they'd have to install gfx engines at Chiswick and Leeds on each regional Tx feed)
Would only work on BBC One SD in England though (and now Plymouth have upgraded it wouldn't splat a PAL footprint on network - apart possibly from Jersey?).
The opting out of analogue sustaining network surely was ditched in all regions shortly after DSO wasn't it ?
The regions would have to remain in 'soft opt' mode throughout, but other than that no issues surely (apart for HD and possibly Jersey ?)
I suspect the vast majority of viewing of Breakfast is SD, on DVB-T1 only receivers in bedrooms and kitchens. In fact, I'm sceptical anybody watches Breakfast in HD in England given the lack of opt outs, and the fact
BBC 1 HD is hidden away way up the EPG
(Thousands of HD equipped viewers are probably still unaware it even exists)