405 Freeway's southbound lanes closed in Los Angeles after brush fire reported

The southbound lanes of the 405 Freeway were closed in the San Fernando Valley on Saturday night after a brush fire broke out, authorities said.

According to the Los Angeles Fire Department, the blaze was reported at 6:27 p.m. on a one-quarter of an acre of grass burning north of Burbank Boulevard in the Sepulveda Basin.

A Sigalert was then issued, and the CHP confirmed all southbound lanes were closed at Burbank Boulevard. Two lanes opened up by 8 p.m.

No injuries or threats to structures were reported.

The closure caused a massive traffic backup. Aerial images showed drivers stuck on the freeway, with some driving across shoulders and over curbs to get to nearby off-ramps.

It's not yet clear how long the closure will last.