What is freezing fog?
Freezing Fog
Freezing fog is a type of fog composed of supercooled water droplets. These droplets remain in a liquid state even when the air temperature is below the freezing point of water (0°C or 32°F).
Formation
It forms in a similar way to ordinary fog, but requires temperatures below freezing. Conditions that favor its formation include:
- Clear skies and light winds: These conditions allow for significant radiational cooling, which lowers the air temperature.
- High humidity: A high moisture content in the air provides the necessary water vapor for fog formation.
- The presence of condensation nuclei: Tiny particles in the air (e.g., dust, pollutants) act as surfaces for water vapor to condense upon.
Characteristics
- Supercooled water droplets: The defining feature of freezing fog is the presence of liquid water droplets at sub-freezing temperatures.
- Ice accretion: When these supercooled droplets come into contact with surfaces that are at or below freezing, they immediately freeze, forming a coating of ice called <a href="https://www.wikiwhat.page/kavramlar/rime%20ice">rime ice</a> or, in some cases, glaze.
- Reduced visibility: Like regular fog, freezing fog can significantly reduce visibility, making travel hazardous.
- Hoar frost: In some cases, freezing fog can also lead to the formation of <a href="https://www.wikiwhat.page/kavramlar/hoar%20frost">hoar frost</a>, which is a deposit of ice crystals formed by direct deposition of water vapor to a solid.
Hazards
Freezing fog poses several hazards:
- Icy surfaces: The ice that forms on roads, sidewalks, and other surfaces can make them extremely slippery, increasing the risk of accidents.
- Reduced visibility: The low visibility associated with freezing fog can make driving and flying dangerous.
- Damage to infrastructure: The weight of ice accumulating on power lines and other structures can cause them to collapse.
- Aviation hazards: Ice accretion on aircraft can affect their performance and handling, increasing the risk of accidents.