Firefighters Thursday doused hot spots at the site of a brush fire that scorched about 60 hillside acres and prompted voluntary evacuations at a mobile home park, authorities said. The blaze started for unknown reasons around 2 p.m. Wednesday in brush just off Mission Gorge Road east of Golfcrest Drive, said Maurice Luque of the San Diego Fire-Rescue Department. Flames raced uphill, burning about 30 acres in the first 15 minutes, then slowed at the top of the hill, where the fire ran out of fuel and was attacked with numerous water drops by the California Department of Forestry, Luque said."The steep, rocky hillside the fire burned up is 1,500 feet (high), Luque said.The SDFRD's Lee Swanson said firefighters heading to the blaze in the first few minutes saw "a big column of smoke." Authorities used loudspeakers to call hikers down from the popular Cowles Mountain Trial. Even though there was only a "minor threat posed" to residents at the Highland Mobile Home Park on the extreme western edge of Santee, they were urged to evacuate voluntarily. The spread of the flames was all but stopped by 4 p.m. Wednesday, and the last of the remaining firefighters left the site before 9, authorities said."There was virtually no wind -- it was not a factor," Luque said. "But the brush is so dry it virtually explodes."About 80 San Diego firefighters were assisted by crews from fire departments in the East County.Mission Gorge Road was closed between Father Junipero Serra Trail in San Diego and West Hills Parkway in Santee throughout the afternoon. No injuries were reported and no structures were damaged. Hand crews returned to the area Thursday morning after hot spots were reported about 4 a.m., a dispatcher said, adding that a helicopter would be sent to check on the site.