What type of cloud is likely to produce light to moderate icing?

The type of cloud that is likely to produce light to moderate icing is alto-cumulus. This is primarily because alto-cumulus clouds form at altitudes between approximately 2,000 to 6,000 meters (6,500 to 20,000 feet) and are primarily composed of water droplets. When temperatures within these clouds fall to the freezing point or below, the supercooled water droplets can exist in a liquid state, which creates conditions for icing as the droplets can freeze upon contact with aircraft surfaces.

Alto-cumulus clouds are characterized by their puffy, white, or gray appearance, often occurring in patches or layers that may suggest atmospheric instability. While they are not as violent as cumulonimbus clouds, which are known for severe weather, alto-cumulus can still create a risk for light to moderate icing due to the presence of supercooled droplets.

In the case of stratocumulus clouds, although they can produce light precipitation, they generally do not produce significant icing because they often form in stable air where the temperature is not conducive to supercooled liquid water. Cirrus clouds, being thin and wispy, typically do not produce icing due to their high altitude and the absence of liquid water.