Let's start with the state of the runway. It is not the airline's prerogative to decide whether the plane takes off or not, but the pilot's. Since he has control over his aircraft, it is up to him to make the decision. As for what influence this will have on our activities, that is generally up to the individual pilots. It's up to them to make the decision.
Then there is de-icing. This takes as long as it takes and depends on the thickness of the ice cover on the wings. I believe other airports have experienced the same situation. Often, when the aircraft returns to the runway and is about to take off, the ice has continued accruing and the operation has to be repeated. You end up going in circles and it is then better to stop operations than to de-ice for the sake of de-icing.
I can't give you precise figures, but it is clear that these conditions slow down operations significantly.