If snow and ice on the sidewalk is frozen so hard that it cannot be removed without injury to the pavement, the owner of abutting property, within the time specified in Section 11.42.020, shall strew said area with ashes, sand, sawdust, or some other suitable material and shall as soon thereafter as the weather permits thoroughly clean such area. Any owner shall not be deemed to be in violation of Section 11.42.020 when sand, ashes, sawdust, or other material is strewn on sidewalks to comply with this section. (Ord. 79-82 §3, 1979).