Yesterday night the ramp operations was stopped for about two hrs from 21:45 to 23:45. Many flts did not arrive 'til after midnight.
regarding the airbus ratio at YYZ, I would say most of them are airbuses. All major Canada carriers fly airbuses such as AC's 340, 330, 320, 319/ TS's 330, 310/ SV's 330, 320. Most regional flts are operated by A320s.
For a single route, frequency can be up to 12 flts a day. That's why most of the diverted are airbuses. Though, AC also flies 744s, 767s and a few 737s from ex-Canadi>n Pacific International.
BA 744 was diverted when the weather was most severe, and later BA 777 also arrived late. (As a result of late arrival, departure also delayed: ATD was 23:00 compared to STD was supposed to be 20:55)
Foreign airlines flying airbus into YYZ are as follow,
Those flying boeing :