Heathrow Redux
Same thing happened last year at Christmas. Flew from GVA to LHR a day late (flights were totally cancelled the day I was to have flown). Got to LHR and found the YVR flight had been cancelled. Had to stay at a hotel (courtesy of BA). Got out the following day but I know that some people didn't get out for days.
What I heard was that a) LHR had literally no de-icing machines and b) staff could not get into work. Personally I think that YVR handles snow much better (at least we don't freak and shut the airport with 2 cm of snow).
that's my two cents.