ST. LOUIS — As the first freeze of the season settled across the bi-state area, areas of river or steam fog developed late at night into the early morning hours.
Viewer Donna Burgess shared these photos along the Mississippi River looking from near Godfrey, Illinois, of the early morning fog Wednesday.
According to the Army Corps of Engineers, Mississippi River water temperatures are still in the middle 50s through the St. Louis area. As overnight lows dropped into the 20s and lower 30s with nearly calm winds, fog developed along the river and in some cases slowly spread into nearby areas.
As the warm river water evaporates, it is quickly cooled as it encounters the drastically colder air, forming fog. The fog can become locally dense along the river valley locations but it usually doesn't drift too far from the water.
As temperatures warm during the morning, the fog usually dissipates quickly.
This cycle will become less frequent as the water temperatures in the area rivers drop as the season changes.
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