At least three separate grass fires kept Sacramento County firefighters busy on Sunday. All three fires were near homeless encampments that had to be evacuated, authorities said. No one has been reported to be injured.At least 14 acres burned near Mather Boulevard and Douglas Boulevard, which is northeast of Mather Regional Park. Ground and air crews worked to put out the fire, the Sacramento Metropolitan Fire District said.A second vegetation fire burned behind a gated community in Carmichael. The approximately three-acre fire started around the area of Sarah Court Park along the American River, Metro Fire said. Forward progress has been stopped. A third grass fire burned near Elkhorn Boulevard in North Highlands, Metro Fire said.It's unclear how many acres have burned. Authorities are investigating the cause of all three fires.No other details have been released.