The safety in regards to the winters , which affected the tarmac , making it undrivable , was one of the reasons why the Mont-Tremblant circuit was closed down and alternated the site of the Canadian Grand Prix .
But when the Mont-Tremblant circuit had been closed down because of safety regarding the bitter winters seriously affecting the tarmac , rendering it undriveable and a dispute with the local racing authorities there in 1972 the alternating of the race stopped and Mosport solely continued to hold the Canadian Grand Prix from 1971-1977 .
Canadian Grand Prix