Why does water vapor appear to rise from a river in very cold weather?

Answer 1

The water vapor is always rising from the river but when the air is cold, the vapor condenses to droplets almost as soon as it hits the cold air.

Answer 2

This occurs due to the water retaining energy longer than the surrounding land. When the winter months roll around, the water still remains warm relative to the surrounding land, and since air will take on the qualities of the surface below it, the air also becomes colder than the water. Because of this, the water molecules near the surface of the water, which are constantly leaving the river to be become vapor and re-entering the river upon condensing, condense at a much higher rate due to the extreme temperature difference; kind of like being able to see your breath on a cold day.

Now, since the river is warm (again, relative to the surrounding air) the air above the wate will begin to rise-warm air is less dense than cold air- allowing you to see the condensed water rising off the water. As this air enters the much drier air farther above the river, the water will evaporate back to vapor.

This phenomena is the reason why lake effect snow occurs. The Great Lakes are warm and moist, and the air blowing across them is cold. If the winds blow across the lakes with the proper orientation, lake effect snow will be produced from the rising air off the lakes.

Answer 3

This is called steam fog. It occurs when cold air is resting over warmer water. The thin layer of cold air just above the surface of the water is heated by the warmer water. This warm air layer is capable of holding additional moisture so some evaporation of the water takes place. As this warmer, moist air rises, it quickly cools, condensing out the added moisture to form the steam fog.

Answer 4

It is one of two things....either the water is warmer than the air...or the air is warmer than the water....creates moisture vapor.

Answer 5

It has with the vapor pressure to do