single word requests - What is the white smoke-like fog called?

It's not really fog, mist or haze. I used to think that it's mist, but from what I've read here, it turns out that it isn't.

It's the white smoke-like fog that is close to the ground. I've seen it recently above a couple of small ponds (and ground) in a damp forest. It was almost as white as smoke, you can barely see through it, but it is close to the ground, from 20cm to a meter or so.

Since it isn't fog (which is a cloud that you can see, say from a mountaintop, and if it's not mist (which is more like 'rain'), then what is it?

Answer

Some kind of radiation fog (ground fog is a synonym):

Radiation fog is formed by the cooling of land after sunset by thermal radiation in calm conditions with clear sky. The cool ground produces condensation in the nearby air by heat conduction. In perfect calm the fog layer can be less than a meter deep but turbulence can promote a thicker layer. Radiation fogs occur at night, and usually do not last long after sunrise, but they can persist all day in the winter months especially in areas bounded by high ground such as the Vale of York in England. Radiation fog is most common in autumn and early winter. Examples of this phenomenon include the Tule fog.

Ground fog is fog that obscures less than 60% of the sky and does not extend to the base of any overhead clouds. However, the term is usually a synonym for radiation fog.

[ Wikipedia ]

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