Well it isn't much of a case if you are saying that only Luton will be closed for hours when it snows?
I think you need to read post 3086 again and absorb the articles.
What can and does happen is that only Luton can be affected by snow when airports like Stansted and Heathrow remain open.
Take a look at
United Kingdom Weather before the days out for hourly weather reports for the last 24 hours.
Luton 4 hours of continuous light snow
Heathrow no snow
Stansted no snow
Gatwick no snow
London city no snow