What type of clouds produce the heaviest icing potential during winter?

During winter, the heaviest icing potential is predominantly associated with nimbostratus clouds. This type of cloud is characterized by thick, uniform layers that produce steady precipitation, often in the form of rain, snow, or drizzle. The conditions within nimbostratus clouds include a relatively stable atmosphere and consistent moisture content, which contribute to the formation of supercooled water droplets that are capable of causing significant icing on aircraft surfaces when temperatures drop below freezing.

While other cloud types like cumulonimbus can produce icing, they are more commonly associated with severe turbulence rather than extended icing situations. Similarly, while stratus clouds can produce some light icing, they are not known for significant freezing precipitation when compared to nimbostratus. Cumulus and TCU clouds, although associated with convective activity, typically do not lead to the sustained, heavy icing conditions that nimbostratus clouds can create. Therefore, the presence of nimbostratus clouds during winter presents the highest potential for aircraft icing due to their persistent precipitation and ideal conditions for supercooled droplets.