The potential for in-flight icing during an IFR flight—regardless of whether the airplane is approved for flight into known icing or not—means doing serious plotting and scheming prior to departure, and throughout the flight. As has been demonstrated for years, structural icing does bad things to airframes. Best to presume every cloud will contain ice, and plan accordingly.
This is a companion discussion topic for the original entry at https://www.avweb.com/flight-safety/technique/facing-lake-effect-conditions