Crews are battling a grass fire north of Saskatoon near Highway 16 and Range Road 3062.The Saskatoon Fire Dept. received a 911 call at around 2:30 Tuesday afternoon about a controlled burn that had become unmanageable.Firefighters are currently working to extinguish the fire that has expanded across a significant area.Water tankers are being used to shuttle and store water until needed for use by the brush trucks.A farmer is assisting in controlling the spread of the fire with the use of a tractor.The incident is ongoing.