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I have seen caves fog during very cold days but sometimes I really wonder if caves fog on rainy days.... (cold or not) This evening it was around 70F and I was peering out my window and noted that fog kept originating from one spot on the mountain and constantly drifted upwards (similiar to chimney smoke). I have noticed this in other places on my caving journeys but was curious if any of you have actually found caves because of this or know of caves that do fog during rain events.

Some caves might fog on rainy days, but I doubt that is what you are seeing. I have often seen the same thing occuring on mountains near my home- where I am certain there are no caves whatsoever. Sorry to burst your bubble, but it is probably not cave-related.

Trogman

Thanks Trogman,

The area I am seeing the fogging is being issued from an area that contains limestone. Most of this area does! I think the best way to do this would be to remember the spot and see if it does it again on the next rainy day (although im sure it's more complex than this). If so, I may have to go check it out.

I saw the same thing happening on a hillside one time and decided to chase it down. I went up the mountain directly toward the fog I was seeing. Shortly I found the fog and the source. It was a tree that seemed to be giving off a mist. I was extremely disappointed. This was during summer
and apparently the greenery on the tree was producing some kind of fog after a light rain.

I have seen fog coming from caves during extremely hot weather and extremely cold weather. In cold weather, a fog is much easier to see if
sunlight is streaming through the fog. The fog is strongest at or below 20 degrees F. The cave I saw fogging in the summer was after a rain and there were cattle cooling off near the entrance. It seems in summer that fog is most likely to occur when cool moist air hits warm moist air. Those conditions are best just after a rain on a hot day. 90's and above are ideal.

Thanks tncaver!

It was only 70F here yesterday when I saw the fog so, I assume from your posts that it was probably some other phenomena... Thanks for the reply!

I can only recall seeing fog/mist rising out of cave entrances in the winter- at least as pertains to higher elevation caves. Occasionally I have noticed fog coming out of valley floor entrances (Limrock comes to mind), especially after rain events. Those who have driven up Rocky Lane on Pigeon Mt. in cold weather have probably seen the mist spewing out of North Bend Sink Cave. It looks like a steam engine locomotive, and can be seen from a pretty good distance.

Trogman

Fog from caves would be produced by moist cave air coming out into colder air and the water vapor condensing into small droplets. Trees and other vegetation can also draw massive amounts of water from the soil and put it into the air. If it's really hot outside then rain making contact with cooler cave air might also produce fog. I don't know how much elevation change is in the area in question, but upslope fog due to air masses moving up a mountain and cooling can also be a fog source.