Things have improved a lot at the YYZ CDF since 13 years ago. But the devil is also in the details and I'm going to bet that this LR35 flight was trying to depart during the late afternoon / evening rush, which in those days, was a recipe for serious delays when it snowed. Anyone who worked out of YYZ at that time knew all of this, and any flight planner worth their paycheque included extra fuel to account for it (as much as possible).