Three wildfires have burned more than 3,500 acres this week in Southern California and triggered evacuation orders and warnings for tens of thousands of residents in Ventura and Riverside counties.

Multiple wildfires burning across Southern California have prompted health warnings for residents and a smoke advisory throughout the day Thursday.

In Simi Valley, tens of thousands remain evacuated as firefighters work to make progress on the Sandy Fire, which erupted late Monday morning and destroyed at least one home.