LOS ANGELES, Oct. 24 (Xinhua) -- Some 40,000 residents were evacuated on Thursday after a fast moving brush fire near Los Angeles threatened 10,000 structures.

The fire, dubbed Tick Fire, was reported in the city of Santa Clarita, 60 km northwest of downtown Los Angeles and moved quickly downhill toward Canyon Country, a residential community nearby.

The local KTLA news channel reported that the flames had spread to 200 acres (0.8 square km) within 20 minutes and scorched over 3,950 acres (15.9 square km) by 8:00 p.m. local time.

Aerial video from local ABC7 news channel showed that some outdoor structures were damaged and the flames were dangerously close to homes in some areas.

About 500 firefighters were battling the blaze on the scene with six helicopters and four airtankers, but their efforts were hampered by poor weather, according to local authorities.

"Firefighters are faced with a strong Santa Ana wind this evening and into Friday," the Los Angeles County Fire Department said in a statement issued Thursday night.

The fire came amid red flag warnings issued for some areas in Southern California due to extreme wildfire risk.