Fog creeps in
Be cautious of this insidious weather phenomenon
Flying in fog is challenging, even for the most experienced pilots.
According to the NOAA Aviation Weather Center, approximately 440 people are killed each year in weather-related accidents, including the conditions of low visibilities and ceilings. If you are planning a flight and it’s foggy, or there will potentially be fog, follow these safety guidelines from the NOAA Aviation Weather Center:
- Get the latest forecasts, advisories, and observations.
- Follow the flight rules for the flight category based on visibility and ceiling height. The ability to fly in fog depends on three factors: the capability of the pilot (i.e., an instrument rating), the capability of the aircraft, and the capability of the airport.
- Know the layout of the airport you are departing from or arriving to, including the length and orientation of the runway.
- Be aware of the potential for freezing fog; if temperatures are at or below freezing and fog is present, a layer of ice may form on the airplane.
- Always file a flight plan.
Radiation fog: Temperatures drop to the dew point, and fog forms at the surface during the coldest hours of the night.
Advection fog: Moist air moves over a colder surface.
Upslope fog: Moist air is cooled as it flows up the windward sides of mountains.
Valley fog: Cold, dense air sinks and pools, often over a river.
Frontal fog: Warmer air advances over colder surfaces.
If early-morning fog is sitting over your airport, just wait; fog typically develops overnight and dissipates in the early morning sunlight hours. When the air warms, the temperature will increase above the dewpoint. When conditions are saturated in the air at the Earth’s surface, the temperature equals the dewpoint.
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