And no, actually in response to the poster above. You don't just let the snow build up. You keep it clear as that is quicker and more effective. Once snow builds up it is heavy and hard to shift, it also doesn't allow the ground to absorb heat from the sun, which then melts the remaining thin layer.
But ultimately I think the City's problem is just not enough staff to do this work.
I am well aware of how to clear snow. If you read my post again you will see that nowhere in there do I suggest letting it build up. My point is merely that IF it snows hard enough for long periods of time (specially in the kind of winds we have been having) there is very little that can be done about it closing a runway. Specially at the city where they only have a couple of decent runway sweepers. It just isn't a common enough occurrence to justify spending on vast ammounts of winter ops equipment. BFS are actually surprisingly well equipped for snow given the usually mild winters we have in Northern Ireland.
From my understanding, staff is not the issue at City, they have a well stocked Airside Standards dept who look after the apron. I think the fire service there is responsible for the runways and taxiways and in the winter they have an off duty fire crew on standby for winter ops (although my info is probably out of date by a couple of years)