Firefighters are battling Oregon's Flat Fire covering 22,000 acres and threatening hundreds of structures despite recent weather improvements and new containment lines.

Ten structures — including four homes — have been destroyed by a wildfire sweeping through central Oregon as thousands of homes in the state and in Northern California wine country remained under evacuation orders Monday.

Four homes have been lost to the Flat Fire as it continues to threaten nearly 4,000 homes in Deschutes and Jefferson counties.