Topanga Canyon could remain closed into the fall after massive landslide

A massive landslide covering a large section of Topanga Canyon Boulevard still poses a safety risk and may not be cleared until fall, the California Department of Transportation said.

Recent storms further saturated the unstable hillside, Caltrans officials said.

Water has been seeping beneath the dirt, mud and rocks — an indication that the land may move again. That is particularly concerning, officials said, because a large boulder sitting about 10 feet high has developed a crack that is 5 to 10 feet wide.

The unstable hillside poses a challenge as well as a safety risk for crews who must bring material from the top of the hillside to the ground.

The roadway is closed from Grand View Drive in the community of Topanga to Pacific Coast Highway.

The landslide was one of several that occurred last month after a series of winter rainstorms drenched Southern California, dumping more than a typical year’s worth of rain on the region in a matter of weeks.

Caltrans officials estimate the landslide is 8,000 cubic yards and weighs about 9.2 million pounds.

“That is enough material to fill 5,500 dump trucks,” officials wrote in a statement.

The landslide, they said, is twice as large as another major slide that occurred in the 1940s. Officials did not know how long it took to clear that one.

Topanga Canyon Boulevard, also known as State Route 27, is one of the busiest roadways running from PCH to the 118 Freeway.

Officials said temporary traffic lights have been placed at Tuna Canyon Road and PCH as a safety measure.

On Sunday, a rockslide closed Malibu Canyon Road - just north of Pepperdine University - in both directions in the Santa Monica Mountains. Malibu Canyon Road tunnel was closed until late Monday afternoon, officials said.