Which condition is linked to significant in-flight icing?

Significant in-flight icing is closely associated with clouds that have temperatures below freezing. When an aircraft flies through these clouds, supercooled water droplets can be present. These droplets remain liquid despite being below 0 degrees Celsius, and when they come into contact with the aircraft's surfaces, they can freeze upon impact, leading to the accumulation of ice. This phenomenon is particularly prevalent in clouds such as cumulus or nimbostratus that contain moisture and have the right temperature conditions for icing to occur.

In contrast, flying through clear skies does not provide the moist conditions necessary for icing to develop. Severe turbulence in warm air masses is more likely to involve warmer temperatures where ice formation is unlikely. High altitude winds above 20,000 feet can also be found in various atmospheric conditions but are not directly tied to the creation of icing, as the temperature and moisture levels in those regions are what primarily influence icing risks.