135.12 DUMPING OF SNOW.
   It is unlawful for any person to throw, push, or place or cause to be thrown, pushed or placed, any ice or snow from private property, sidewalks, or driveways onto the traveled way of a street or alley so as to obstruct gutters, or impede the passage of vehicles upon the street or alley or to create a hazardous condition therein; except where, in the cleaning of large commercial drives in the business district it is absolutely necessary to move the snow onto the street or alley temporarily, such accumulation shall be removed promptly by the property owner or agent. Arrangements for the prompt removal of such accumulations shall be made prior to moving the snow.
(Code of Iowa, Sec. 364.12[2])