On the origins of "superfog" -a combination of smoke and water vapor that produces zero visibility over roadways
Southern land managers use prescribed fire to treat 6 to 8 million acres (2-3 ha) of forest and agricultural lands in the Southern states each year. Although the vast majority of prescribed burns are carried out without incident, there are occasions when meteorological conditions combine with residual smoke to compromise visibility. Multiple-vehicle pileups, numerous physical injuries, extensive property damage, and fatalities have been associated with visibility reductions due to smoke or smoke and fog on roadways. Most serious accidents occur during the night or at sunrise as smoke trapped in stream valleys and basins drifts across roadways.