If the owners or occupants of property within the city fail to promptly remove accumulations of snow or other obstructions from the sidewalks, or streets or alleys on which their property abuts, when required to do so by ordinance, the manager may have it removed and the cost of removal assessed against the property. The cost of removal constitutes a lien against the property to be collected in the same manner as special assessments.
W.S. 15-4-311