The affected roads could include The Angeles Forest Highway, Big Tujunga Canyon Road and Upper Big Tujunga Canyon Road. They could be closed to all traffic except emergency vehicles and Public Works personnel.
The department says area residents will not be permitted to use the roads until the closures are lifted.
"No Parking During Rain Event" restrictions will be enforced on posted streets in La Canada Flintridge and La Crescenta. Parking is not allowed on posted streets during rain.
Residents are asked to call 211 Los Angeles County Information for information and post disaster resources. The toll-free 211 telephone number is available 24 hours a day and seven days a week.