Yeah, that's the worst. A layer of hard ice with a sprinkling of nice crunchy "dance wax" on top. Perfect for wrenching backs, breaking hips, cracking heads.

When we get a too-warm thaw mid-winter, I try to sprinkle a thin layer of powder snow on the ice during the day so that it bonds as it freezes. If it's really bad, I have been known to start up the Mantis rototiller to chew up the ice surface (laugh all you want, it works). Can't do that around town, though, unless you want them to take you away in a rubber truck.