Just after 10.30am local time (6.30pm GMT), California Highway Patrol reported that Topanga Canyon Boulevard, also known as California State Route 27, had been closed following a huge mudslide.
A Sig Alert has been issued and drivers have been told to use Las Virgenes Road and Malibu Canyon Road as a detour.
There was no immediate report of any injuries and the full extent of the slide has not been confirmed.
Earlier the National Weather Service in Los Angeles, just east of Malibu, tweeted: “Rainfall intensities beginning to increase in Malibu and Santa Monica Mountains. Big Rock Mesa reporting 1 hour rate of 0.32″ as of 9 am.”
More to follow…
This is a breaking news story – refresh for updates.