When does the heaviest icing conditions typically occur?

The heaviest icing conditions typically occur in the temperature range of -10°C to 0°C. This range is particularly conducive to the formation of supercooled water droplets in the atmosphere, which are a primary cause of ice accumulation on aircraft. These droplets remain in a liquid state even at sub-zero temperatures and can freeze upon contact with an aircraft surface, leading to significant ice accumulation.

At temperatures around -10°C to 0°C, the conditions are often ideal for this type of icing because the increased moisture content in the clouds at these temperatures allows for more abundant supercooled droplets. In contrast, at temperatures warmer than 0°C, icing is less likely to occur as the droplets are generally in a liquid state and can evaporate. As temperatures drop beyond -10°C, the likelihood of supercooled liquid water decreases, and ice crystals are more commonly encountered, resulting in different icing characteristics that are often less severe than those found in the -10°C to 0°C range.