At least three people are dead in rural North Dakota after tornadoes left damage across eastern areas of the state, the Cass County Sheriff’s Office said in a release Saturday.

Three people are dead and a regional airport was heavily damaged after powerful winds, including a tornado, swept across the upper Midwest, while nearly 150 million Americans were under a heat advisory or warning.

At least three people are dead in North Dakota after severe weather swept across the region on Friday night, authorities said.