How could a region have a (semi-) permanent mist/fog?

As close to natural as possible but possible enhancements are an option like:

  • Technological : can both be chemical or mechanical but should make little to no noise and should work with limited resources.(limited to pre 1900ish era tech)

  • Mutations: For example mutated flora that could produce something
    like this if (heavily) mutated.

  • Open For suggestions really.

This mist/fog should be able to hide small nomadic groups( ~20 to 50). With hostile patrols/travelers rarely entering the area.

The environment: Mainly Bogs(And other wetlands)/forests(Spruce, Pine, Beech, Oak, Birch & Ash). Located close to a sea on the northern hemisphere with a colder (but not freezing) climate. Also no Volcanoes above or below ground.

Size of the area around 10,000 to 40,000 KM2 (but not everything would have to be covered at once)

To be clear it's about the (possible) origin of such an event, not the effects it would have on society :)

My first question here so any improvement suggestions are more then welcome :)

  • $\begingroup$ should there always be fog or do you want the intensity to just change from time to time, so there is at least some fog at any given time? $\endgroup$ – Tobias F. Nov 20 '19 at 9:21
  • $\begingroup$ @TobiasF. Always a thick fog, but the range of it can be a variable (covering less ground) $\endgroup$ – A.bakker Nov 20 '19 at 12:07
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    $\begingroup$ So the book is set in "Scotland" ! :) $\endgroup$ – Fattie Nov 20 '19 at 16:30
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    $\begingroup$ @BKlassen These questions are not duplicates. That question is concerned with seeking the ramifications of having perpetual fog, while this question seeks a way to create perpetual fog. $\endgroup$ – Frostfyre Nov 20 '19 at 18:32
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    $\begingroup$ @BKlassen as Frostfyre said, that question is about the effects of an area under permanent fog, not on how such a fog could exist. $\endgroup$ – A.bakker Nov 20 '19 at 18:42

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This is a picture of the town of Grand Banks, Newfoundland. The Guiness Book of World Records states it as being the foggiest place on Earth. Here, cold sea currents from the North meet up with the much warmer Gulf Stream from the south. This creates up to 206 foggy days per year, so well over half a year of fog in total.

With a little stretch of the imagination, you could plausibly set your fictional country in a cold, coastal region far up North, where a similar but stronger phenomenon happens, in order to generate almost year-round fog. Maybe instead of a warm current it's actually (underwater) volcanoes that generate the warm water that combine with the colder water to form fog, so that the fog would be even more consistent and permanent.

  • $\begingroup$ Useful but not quite there yet haha. It's a cold northern coastal area but no real warm front or volcanic activity. $\endgroup$ – A.bakker Nov 20 '19 at 14:48
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    $\begingroup$ @A.bakker To be fair, the Gulf Stream isn't a warm front, but a current of warmer water coming from farther south. A volcano is also plausible even if the area is generally not mountainous or volcanic. You'd just need a single relatively young "hot spot" like the one that created the Hawaiian island chain. $\endgroup$ – MrSpudtastic Nov 20 '19 at 15:22

For a very limited area, a cool breeze blowing out of a cave system into a warmer and always-damp climate will do the job. As long as the cool side is below the dew point of the damp side, you'll get condensation -- though it might sometimes take the form of drizzle or light rain when the fog gets above ground level.


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