It's a good question as to how airports can actually clear snow without any disruption to air transport movements where snow clearing is required. If an airport has the capability to plough / sweep and or blow snow in one pass of the runway, some critical factors in avoiding disruption would be aircraft spacing, rate of snow fall and sweeping speed.
As far as I am aware, some Scandinavian airports claim to never close, not never to suffer from disruption. I don't think anyone involved in snow clearing would take that kind of liberty with nature. Claiming to never close is already pushing your luck.
Many of our practices are down to culture. I can remember landing in a passenger jet with no fire cover present up in the arctic. This appeared to be culturally acceptable, given no medical facilities in the area either, but not elsewhere.