Multiple wildfires, including the Palisades Fire and Eaton Fire, are raging across southern California Thursday, leaving at least 5 dead and burning more than 27,000 acres, officials say. Police have arrested 20 suspected looters.

The Palisades and Eaton fires are threatening homes, with winds expected to intensify. California Gov. Gavin Newsom described the fires in Los Angeles as “unprecedented.”

Tens of thousands of people have fled their homes as a brush fire in the Pacific Palisades has grown to nearly 20,000 acres on Thursday.

While the cause of each blaze has yet to be determined, all burned in or near foothill communities amid gusty winds and dry air and vegetation.

The huge, fast-moving fires are stretching the region’s firefighting resources and have become the most destructive in the history of Los Angeles.