Originally Posted by IO540
Freezing rain occurs when snow falls through a warmer layer and melts.
Actually not quite right,IO540.
Freezing rain, causing translucent rime icing (the dangerous one), occurs when supercooled water droplets fall from a warm sector of a depression through the warm front into the cold sector. In winter, the temperature of the cold sector could well be below zero.
Thus aforesaid supercooled droplets impinge on freezing airframe, freeze on impact (the proportion flowing back and freezing dependent on the actual temp. below zero) and the aircraft is now heavier with a wing displaying much-adjusted lift characteristics.