Yes, fog can turn into light snow under certain conditions. Fog, a visible aerosol of tiny water droplets or ice crystals near the Earth's surface, can produce precipitation, including very light snow. This is particularly true with freezing fog, where the fog itself is at or below freezing. The water droplets within the fog can freeze and precipitate as very light snow. The amount of snow produced is usually minimal, but it can accumulate, especially in areas where the fog is dense and persistent.
How Fog Can Lead to Snow
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Freezing Fog: When fog forms in sub-freezing temperatures (below 0°C or 32°F), it's called freezing fog. The water droplets in freezing fog are supercooled, meaning they remain liquid even below the freezing point. However, they can easily freeze upon contact with surfaces, forming a light layer of rime or snow. As reported on Reddit's r/meteorology subreddit, a user observed very light snowfall resulting from freezing fog.
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Moisture Saturation: At 100% relative humidity, the air is saturated with moisture. If additional moisture is added, the air becomes supersaturated, potentially leading to precipitation, which could be light snow in the case of fog. The amount and type of precipitation depend heavily on the temperature and atmospheric pressure.
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Collision-Coalescence: In some instances, the water droplets within the fog may collide and coalesce, growing larger until they become heavy enough to fall as precipitation. If the temperature is low enough, this precipitation will be snow.
Example: Imagine a scenario where a thick layer of freezing fog settles over a landscape. The moisture within the fog gradually freezes onto existing surfaces, while other water droplets within the fog combine and fall to the ground as a very light snowfall.
It's important to note that the transformation of fog into snow is typically a process of precipitation from the fog itself, rather than a direct transformation of the fog's structure into snow. The precipitation from fog is often light and localized.
