Which type of clouds are classified as special clouds?

Cumulonimbus and Nimbostratus are classified as special clouds because they are associated with significant weather phenomena. Cumulonimbus clouds are towering and can reach high altitudes, often producing thunderstorms, heavy rain, hail, and even tornadoes. Their vertical development indicates strong convection and instability in the atmosphere, making them crucial for severe weather forecasting.

Nimbostratus clouds, on the other hand, are thick, dark clouds that cover the sky and are associated with continuous and steady precipitation. They don't typically produce severe weather like thunderstorms, but they play a significant role in bringing prolonged rainfall and overcast conditions.

The classification of clouds as "special" often refers to their specific roles in weather events and their impact on local and larger scale weather patterns. This distinction highlights their importance to meteorology, particularly in predicting and understanding various weather systems.