With friends, we had the same issue : fog may be a pain in the ass on Tanoa.


You need to:
- put an admin password in settings of the private server
- install the mod NSS Console. It provide a debug console

Each time we start the mission, if fog is too dense :
> Open message box : #login my_password => You will have confirmation you are logged as admin
> Open Console : Shift+F1 => The console appears
> Enter : 0 setfog 0
> Execute as "server exec" => Fog will disappears quickly