The Los Angeles County Sheriff's Department has urged residents of 147 homes in La Canada Flintridge and 85 residences in adjacent La Crescenta to comply with the order by 9 p.m. Tuesday as a safety precaution.
Public works and emergency agencies have been monitoring the threat of debris flows and mudslides in the communities since last year's Station Fire, an arson-caused blaze that burned away vegetation on 250 square miles of the San Gabriel Mountains.
Rain has been falling on the area since late last week.
The Associated Press contributed to this report.
