CBC Web Article
I was leaving my office 8 miles south of the accident site a few minutes after it happened. The rainfall was like driving through a carwash and could have been the same cell as they had been moving south on the radar pictures for the last few hours.
The satellite pictures initially showed two bubbles coming South from Tobermory that blossomed into CBs. The CB line eventually stretched along the Niagara Escarpment from Tobermory to Port Credit and eventually to Buffalo. The satellite images are considerably wider than the radar images which showed a tight band of rainfall.
The satellite images will be available for some 24 hours:
Canadian Satellite Images
I don't know how to retrieve archived radar images. If anybody can, look at Buffalo, King and Britt -- it was quite a show.