AZUSA, Calif. (KABC) -- Thousands were evacuated from campgrounds and day use areas after a a second alarm brush fire broke out Sunday afternoon in the Angeles National Forest north of Azuza, officials said.The fire, dubbed the Tecolote Fire, sparked at about 2:30 p.m. and spread across 350 acres at Highway 39 near Mile Marker 28 and was at 0 percent containment by 5 p.m., said Nathan Judy, a spokesman with the U.S. Forest Service. By 8 p.m. the fire had reached 400 acres and 5 percent containment.Eight helicopters and 200 firefighters were sent in the initial response, officials said. Hot temperatures and tough terrain remained a challenge for firefighters battling the flames, Judy said. One firefighter was treated for heat exhaustion.Areas near the river and lake were evacuated, including Coldbrook campground, which includes 22 sites, and about 20 recreational cabins. The U.S. Forest Service believes it has gotten everyone in the evacuation areas out, Judy said.Crystal Lake campground has not yet been evacuated, but campers were placed on standby. Authorities were monitoring the situation at Bear Creek hiking area. The California Highway Patrol closed Route 39 at Encanto Park to all traffic.No residential homes were impacted as flames burned deeper into the forest and away from communities. Azusa and Glendora police said the fire was no threat to their respective cities.