Freezing fog is a significant concern in aviation due to its potential to impair visibility and cause dangerous ice accumulation on aircraft surfaces. It occurs when supercooled water droplets remain in a liquid state at temperatures below freezing. When these droplets come into contact with an aircraft, they can freeze instantly, leading to the formation of rime ice on critical surfaces such as wings, propellers, and engines.

How does freezing fog form?

Freezing fog typically forms under specific meteorological conditions. It occurs when the air temperature is below 0°C (32°F) and there is a high level of humidity, often associated with calm winds and stable atmospheric conditions. These conditions are most common during the winter months when cold, moist air is trapped near the surface by a temperature inversion. Freezing fog is especially prevalent in areas with significant temperature fluctuations, such as valleys and areas near bodies of water, where cold air can pool and lead to prolonged periods of fog.

Freezing fog is most frequently observed during late fall, winter, and early spring, particularly in temperate regions of North America, Europe, and Asia. In these regions, the combination of low temperatures and high moisture content in the atmosphere creates ideal conditions for freezing fog formation, often impacting aviation operations during these times of the year.