Tornadoes and flooding spawned by severe thunderstorms tore through parts of Oklahoma overnight, leaving at least 11 people injured and shredding homes and other properties.

Severe weather swept through eastern Oklahoma early on Sunday, including at least six tornadoes that touched down, the National Weather Service said.

The storms caused "extensive damage to residential and commercial properties," and knocked down power lines, traffic lights, and trees throughout the area, the fire department said. By Sunday night, more than 17,000 people were without power — down from the nearly 82,000 people left in the dark Sunday morning, according to poweroutage.us.