It shall be the duty of the city to give notice to any owner, tenant or occupant, or the agent of any owner of any property to remove snow, ice, weeds, litter and/or obstructions, from any sidewalk, which notice shall be sent by registered mail to the last known address of such owner, tenant, occupant or agent. The owner, tenant, occupant or agent shall have not more than twenty four (24) hours from and after receipt of such notice, within which to remove the snow, ice, weeds, litter and/or obstructions as set forth in the notice. (1990 Code § 12.04.150)