This was a recent risk seminar topic, and the suggestion was to make a best effort to keep the walk clear. However the recommended approach was to advise the municipality, in writing, more than once, about the observed risk. For example, if there is a lifted slab which poses a trip hazard, or an area where sinking pavement or cracked pavement which causes a depression which fills with water, write the municipality describing the situation as accurately as possible, and asking them to repair the hazard.
Several examples were given, and it was urged to include photographs. The presenter urged providing textual descriptions, as photos do not always get included in correspondence forwarded within the municipality.
It was also emphasized to re-report the condition after a reasonable time. That could be a day or a week or longer, depending upon the relative risk.
A municipality can require a resident to clear a walkway/sidewalk, but the obligation of maintenance of the walkway itself is incumbent on the municipality, who owns/installs or dedicates the common walkway. Ponding water, forming an unusually icy area is beyond "clearing" a walkway. However, removing packed snow, or refreeze which become slippery is within the expectations of homeowners.