A few definitions:

permanent - not permanent on the scale of the Earth's lifetime, but good enough to last a couple hundred years - seeming permanent to those who were born there at least.

size of New York City - roughly 305 square miles (491 kilometers)

fog - should consist of water, goal is to achieve visibility below 100 meters (109 yards) while preferably staying around 30 meters (33 yards).

what location? - preferably midwest U.S. but whatever location you need in order to make it work, so long as the land-covered area stays at 305 square miles or larger.

What human-induced disaster could cause permanent fog in an area the size of New York City or larger?

  • $\begingroup$ Does the area need to be compact, or will a long, thin strip work? $\endgroup$ – Mark Jan 5 '16 at 11:07
  • $\begingroup$ @Mark I would prefer compact for my particular scenario, but I think an answer of a long, thin strip still works for the question (because I'm curious), and also, a thin strip could work for me to a point, though probably not as thin as you are thinking, maybe about 10 miles wide. $\endgroup$ – DoubleDouble Jan 5 '16 at 17:00
  • $\begingroup$ The midwest is a pretty bad choice for this set up. Sure fog forms in the region...it did yesterday in fact. The problem is that there are no geographical features to keep the fog in place and the climate hits all four seasons with temps in winter getting to 0 degrees F (and lower on occasion) all the way up to 100 degrees F. If you want an almost always covered in fog place the climate should change less and there should be protection from winds that would blow it away. $\endgroup$ – James Jan 5 '16 at 19:56
  • $\begingroup$ @James That is true, which is why you can use whatever location you need in order to make it work. $\endgroup$ – DoubleDouble Jan 5 '16 at 19:59
  • $\begingroup$ Maybe the weather control station that fights off global warming blows up. $\endgroup$ – Azor Ahai Jan 16 '16 at 5:52

I do not know if this would work but should be sufficient for most fiction.

A city lies above either a tectonic rift or hot spot in a valley with a river. in order to provide geothermal energy to the city. A massive drilling project is started to access this energy. Unfortunately, (much like is reported with fracking) a human induced earthquake/eruption occurs. Fortunately, no lava reaches the surface but a large, high temperature underground lake fed slowly by the river is formed. The lake has no outlet. Cracks in the bed rock and asphalt form through which steam constantly escapes.

While safety controls are in place to stop someone walking into the area, public and legal sentiments prevent plugging or excessive redirection of the vents for fear that increased pressure will result in a larger disaster.

To prevent flooding and generate power, large vents are cooled and condensed in controlled facilities fed by river water. It is impractical to do this for all vents and many vent into the air creating fog. On good days, it rises enough that it rains and the air is relatively clear but those days are rare. Pollutants, dust, and rock particles provide nucleation sites to ensure droplets form close to the earth's surface.

  • $\begingroup$ Clever answer I like it. $\endgroup$ – James Jan 5 '16 at 19:53

Take a coastal city with a very humid climate. Now, it's a decent place to live, but it's only got one problem: it's flat. People want houses on hillsides. So, over the course of a century or two, people bring in landfill to build higher and higher artificial hills. Since it's so humid, once those hills reach the 400-500 meter level, orographic lift starts turning that humid air into clouds. Net result: an urban cloud forest running along a strip of coastline.


There are peatlands around the city. People have build canals and water systems to dry up the peatlands in hope to transform them into soil to be used for growing plants. When peat have dried, the lighting strike, and fire started. If we had enough peat, the fire can be realy hard to estinguish, and it will burn slowly for few years. In real life, the 2008 year's summer was very hot in Moscow, and many small fires in peatlands around Moscow have started. They were lasting until 2011 year - http://blogs.telegraph.co.uk/news/andrewosborn/100049657/moscow-has-been-engulfed-by-an-apocalyptic-fog-could-this-have-been-prevented/

  • $\begingroup$ There are any number of ways you can get a killer smog like that. The problem is getting a long-lasting water-based fog. $\endgroup$ – Mark Jan 5 '16 at 11:07

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