THOMPSON PLAZA, the first enclosed shopping centre in the western provinces, opened for business on November 2, 1961. The Manitoban complex included an F. W. Woolworth 5 & 10, Shop-Easy Supermarket and Hudson's Bay Company department store. 
Photos from F. W. Woolworth Company Annual Report 1961

As one might surmise, Canada's northern exposure contributed to the rapid embrace of the enclosed -and heated- shopping mall by its populace. Open-air centres, such Winnipeg's POLO PARK, were being converted into roofed retail hubs by the mid-1960s.