It shall be the duty of the owner or of the occupant of each and every parcel of real estate in the City abutting upon any sidewalk to keep the sidewalk abutting his premises free and clear of snow and ice, and to remove therefrom all snow and ice accumulated thereon within a reasonable time, which will ordinarily not exceed 12 hours after the abatement of any storm during which the snow and ice may have accumulated. (1993 Code 97.12)