This time last year Marvie flew into Manchester, and all the airports were shut in the North of England, she was airbourne overhead for several hours, diverted to Birmingham to refuel then came back and eventually landed. The problem was that despite having the equipment and ploughs, as fast as they were clearing the snow by the time they reached one end of the runway it had already snowed over the clear ground. They could have affectively cleared it, allowed one or two arrivals and departures, then continued clearing it. When your at that stage, which is depandant no the very local conditions and density of snow falling, you can only do your best. We don't have heated runways (which exist in a few places), and in the same conditions, airports in Canada and Scandanavia have similar problems and issues despite what the media wants you to think.