If this flight was due to arrive in YYZ
initially, then it was weather related.
Icing aloft was reported moderate to severe, and only one runway was open at YYZ
, causing holding up to 40 minutes. As this weather was not forecast until much later, I would guess they did not plan for such a long hold, and diverted to their alternate.
We were tankering fuel into YYZ
last night and thus had the fuel for a long hold. Many aircraft were heading to their alternates. (Ours was YOW
Just because I stopped arguing, doesn't mean I think you are right. It just means I gave up!