With the potential for possible landslides and mudslides due to heavy rain, firefighters and officials want residents to be ready to evacuate if needed.
In Pasadena, crews installed K-rails in February shortly after the Eaton Fire when rain threatened to cause problems.
Pasadena Fire Chief Chad Augustin said crews will be talking to neighbors most at risk.
"A disaster can strike at any time," Augustin said. "We want you to have a go-bag, be prepared to be self-sufficient for multiple days."
Pasadena residents in at-risk areas can get sandbags at the fire department.