In regards to this question I thought about how much snow is shown on the runway and the exits in the movie.
So normally a commercial airport will have a fleet of snow plowers or heaters to keep runways, taxiways and aprons mostly clear of snow. But what is the safety limit on when the airport would have to close down due to too much snow coverage on the runway (not due to heavy snowfall, but due to the runway being covered completely in snow).
I think once the markers are no longer visible you would have a severe problem navigating on the ground or once snow piles up so high that the engines would take in a lot of snow it might also be a problem. But what are the actual limits during which one could safely land an aircraft on a snowy runway? And has it ever happend that someone landed on a runway covered in snow anyways?