A total of 18 firefighting ground crews, four helicopters and two fixed- wing aircraft were battling the blaze that was reported about 2:15 p.m. near the park’s visitor center along Father Junipero Serra Trail.
“Ground crews worked on the fire — which was on the side of Kwaay Paay Mountain — in very difficult terrain that was hard to reach,” San Diego Fire-Rescue spokesman Lee Swanson said.
The fast-moving blaze was about 70 percent contained at 5:15 p.m., he said.
Because of high temperatures, there were fewer hikers in the park than on a normal Sunday. All of them were successfully alerted and evacuated after the fire began, Swanson said.
The extent of the injuries to the firefighter was not known.
Authorities said fire crews will remain overnight performing mop-up operations on the remnants of the blaze.
Mission Trails Regional Park will be closed to visitors Monday and will reopen on Tuesday, Swanson said.