It shall be unlawful to delay, hinder or obstruct any vehicles or equipment engaged in the operation of snow plowing or snow removal in the City streets. After a precipitation of snow of 2 1/2 inches or more, and thereafter until the streets are plowed and cleared of snow, it shall be unlawful for any person to park any vehicle upon any street while said street is being plowed or cleared unless such vehicle is attended by a person capable of operating it. The owner or a person in charge of or in control of any vehicle standing in any street shall move or cause the same to be moved so as not to be in the path of the equipment plowing or clearing the street of snow.