[Imp]

Good one forgot all about that, great for early morning mist for river crossings or valleys hammer it with smoke lasts around 5 turns so you need to get a wiggle on.
You can just save the map if I recall, for more consistent smoke but takes a while buy a vehicle edit smoke dischargers, clone.
Drive across the map discharging in each hex entered then save the map. Seem to remember does not last as long though so only did it once.