The new threat comes as a major weather system sweeps into Southern California.
Fire officials urge people living even near the burn area to prepare and get ready to leave before the rain arrives. Many people appear to be listening.
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Hundreds of people have headed to sandbag stations that are set up all across Los Angeles and Ventura counties.
Officials warn that mudslides can happen with little or no notice, even in areas not normally prone to flooding. For residents, it's just adding to the stress they're already experiencing.
"I'm worried about that because we've had mudslides when there hasn't been fires - major mudslides - so it's just going to be worse," Malibu resident Rose Mataja said.
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The rain is expected to start Wednesday afternoon and continue into late Thursday morning.
In Malibu, most residents were just allowed to return home. Now, Mayor Rick Mullen is urging those who live at the bottom of a canyon to follow any warnings.
"Let's say Bonsall or Ramirez Canyon or Trancas, where some of those big, giant canyons come down, the potential that mud could come down, you should be concerned," he said.
In addition to the fears of destructive mudslides, a Los Angeles County man is suing SoCal Edison over claims that the utility company's negligence caused the Woolsey Fire.
The massive Woolsey Fire started Nov. 8 in Simi Valley near the Rocketdyne facility in the Santa Susana Pass. It quickly triggered evacuations in Ventura and Los Angeles counties.
Since it started, the fire has destroyed more than 1,600 structures and charred 96,949 acres.
Three people have died in the blaze - two found in a burned out vehicle in a Malibu driveway and one person inside an Agoura Hills home. At least three firefighters have been injured.
The cause of the Woolsey Fire remains under investigation.