The fire is burning in in the Mount Lofty Ranges, in the state’s south-east, and is currently uncontrolled.
South Australian Country Fire Service (CFS) has issued a Watch and Act Message for those in Echunga Rd, Snelling Rd, Darby Rd, Fisher Rd near Hahndorf and Echunga.
“Check that the path is clear and go to a safer place. Do not enter this area as conditions are dangerous.
“Conditions are continually changing.”
Smoke from the fire is drifting across Hahndorf and Echunga, the CFS said, as they urged residents to close windows and doors.
It is not yet known how the blaze began.