Which type of icing is typically found in cumulus clouds and most severe at the top of clouds?

The correct choice is clear icing, which is often associated with cumulus clouds and tends to be most severe at the top of these clouds. Clear icing occurs when supercooled liquid water droplets collide with an aircraft and freeze upon impact, creating a smooth and transparent layer of ice. This type of icing is particularly dangerous because it can lead to significant increases in weight, changes in aerodynamics, and can disrupt the performance of control surfaces.

In the context of cumulus clouds, these clouds can produce strong updrafts and are often associated with thunderstorm activity, where supercooled water is prevalent. The most severe icing conditions are typically found in turbulent areas, often near the tops of these clouds, where temperatures can remain below freezing, allowing supercooled droplets to persist and contribute to the formation of clear icing.

Understanding the conditions that lead to clear icing is crucial for pilots, as it emphasizes the importance of avoiding flight in areas where cumulus clouds are present, especially when severe weather is anticipated. This knowledge helps in making informed decisions regarding flight safety.