The heavy rainfall and flash flooding pose life-threatening risks to low-lying areas, roads, highways, and underpasses. Coastal communities have been particularly affected, with flooding, beach erosion, and damage to infrastructure reported in Long Beach, Newport Beach, and Malibu. Mandatory evacuations were ordered in Long Beach for homes along Seaside Walk, and Newport Beach declared a local emergency, closing piers and reinforcing sand berms. Residents are urged to avoid flooded areas and follow local emergency instructions to ensure safety.