In a drastic attempt to control the bushfires burning toward their nation’s largest city, Australian firefighters have deliberately caused two of the biggest fires to merge.

The back burning operations near the Blue Mountains in New South Wales state were done with the expectation that weather conditions will continue to deteriorate and hamper efforts to control the flames. Currently 60 bushfires are burning in the area with 13 completely uncontained.

New South Wales Rural Fire Services Commissioner Shame Fitzsimmons told the BBC the joining of two fires at State Mine and Mount Victoria were done to keep the fires from joining with a third fire.

“We are seeing positive results of these very deliberate, very targeted, very decisive strategies being deployed particularly in relation to back-burning operations,” Fitzsimmons said. Over 1,500 firefighters are now on the scene fighting the blazes.

Parts of Sydney, the nation’s largest city, have been covered in a smoky haze for much of the week and air quality has been at dangerous levels. One man has died as a result of the flames and thousands have either fled their homes or are preparing for an evacuation if the flames continue to move toward the city.

Police say they have been able to determine that two of the bushfires were started by an 11-year-old boy.