Authorities blame severe storms sweeping across southern portions of the U.S. and into the Midwest for the deaths of at least 11 people, including two first responders.
High winds, tornadoes and unrelenting rain have battered large swaths of the country.
Officials say a police officer and a firefighter in Lubbock, Texas, were killed Saturday after being hit by a vehicle at the scene of a traffic accident.
Hundreds of thousands of people were left without power from Texas to Ohio, sections of flooded highways were closed in Oklahoma and Arkansas and hundreds of flights were canceled at Chicago's airports.
