Pacific Coast Highway is open, but Decker Canyon Road remains shut down after the charred and saturated hillsides gave way during the overnight rain.
"It can be surprising, just like what happened in Santa Barbara, it's frightening -- and then the power of the mud," said Alicia Roberts, who lives in Solstice Canyon.
MORE: Latest Southern California seven-day forecast
The muddy and rocky runoff shut down at least one lane of PCH earlier in the day. A driver ended up caught in the sudden debris flow. He wasn't hurt but his car had to be towed out.
"I was driving down, trying to make a left...and all of a sudden I felt something was pushing the car, so this whole thing came down," the driver explained.
Crews were out in force cleaning up the muddy mess as quickly as they could. Several spots along PCH were overrun with mud and debris. Authorities were on high alert for any potential problems.
"Before the rains even come, when they're just threatening, you see plows, bulldozers already set up with engines running, guys in there, you know, working 24-7 -- that's reassuring," said Malibu resident Steve Salvato.
But with more rain on the way, Malibu residents know the risk is high.
The Woolsey Canyon Fire left thousands of acres blackened and bare, which is prime for potential problems. The steep canyons combined with a heavy downpour have many worried about one major threat.
"The mudslides, depending on the rain. Last night, luckily, the rain wasn't a issue," said Lynn Jacob of Malibu. "From what I understand, next week will be pretty challenging so we're ready with sandbags, stocking up with groceries and hunkering down."