SPOKANE, Wash. (AP) — A fast-moving wildfire driven by strong winds and high temperatures swept across northwest Spokane on Saturday before jumping the Spokane River and prompting the evacuation of thousands of people.

The Old Trails Fire started around noon, burning brush and grass in an open area, but quickly spread north and east toward residential areas. Cars lined the roads as people fled their homes, and orange and red flames were visible from the highway.

The blaze sent a plume of smoke billowing over the region, and as of the evening almost 4 square miles (10 square kilometers) of terrain had been burned, said Courtney James, spokesperson for the Washington State Department of Natural Resources.

The cause was under investigation.

“We urge residents of Spokane to heed evacuation orders and to stay alert to changing conditions and evacuations as they are rapidly changing,” James said.

Some structures were lost but officials did not yet have a solid count, said Jessica Watson, a DNR spokesperson for the fire. Firefighters had zero containment as of the evening and the wind continued to blow, she said.

Power company Avista said it implemented public safety shutoffs in the area due to elevated fire risk.

Gov. Bob Ferguson declared a state of emergency Saturday after unusually high temperatures and high winds exacerbated record wildfires across the state. The National Weather Service issued a “particularly dangerous situation” red flag alert for eastern Washington.