As Felix said.....
As one who works where it snows 4 months out of 12, and where 25cm in a day isn't uncommon at all, I would humbly suggest that you don't realize all the implications of being ready to face such a weather event.
Where I worked, during a "snow event", additional staff was called in to coordinate along clear guidelines develloped over years of refining.... and they weren't perfect! Just deciding on what priority each bit of pavement got wasn't easy. .............. hold over time as gone by under the falling snow and they must return to deice.
Your arrival runway is now suffering the same fate and so holding time coming in increases as well.
What I described was at an airport that's ready for snow!! Imagine if yours isn't!
In simple terms it seems to be the case that BAA were plainly not ready for the volume of snow that arrived.
Fail to Plan = Planning to Fail.
I completely agree that it is both unreasonable and uneconomic to hold an infinite resource on standby just in case a particular situation turns up, in this case snow clearing equipment for today. But had BAA been a bit more proactive with pre-travel warnings and pre-emptive consolidations of flights in consultation with the airlines, then much of the disruption could have been "managed" out of existence.
I would hope that in the light of the present financial situation and the previous upsets to the industry that contingency planning would be second nature to the airlines and airport operators, but there seems to be a great lack of communication.
I'm sorry if I seem to be preaching, but getting (often competing) international sites & companies to talk to each other and put contingency plans into place as things will [not might] go wrong is part of what I do for a living.