The gunk has turned up on shorelines from Malibu to Redondo Beach: ghostly lines of charred black bits and melted debris left behind by retreating waves.

The large mounds of fire debris that remain on Los Angeles County beaches have caused concerns about long-term effects on the environment and beachgoers.

Debris from January's wildfires - including ash and burned wood - has been turning up on beaches from Malibu to the South Bay, county officials say.

Winter storms have washed debris from the California wildfires - timber, metal, and sediment - onto Los Angeles County beaches. Officials confirm most of the silt and ash is not hazardous and will naturally wash away,