Carrie Underwood says family hid in safe room during Nashville tornado: 'It was scary'

Carrie Underwood's thoughts were with family and friends back home on TODAY Tuesday after a deadly tornado tore through Nashville and resulted in some frightening moments for her husband and two young children.

The country star, who is in New York City to promote her new book, said husband Mike Fisher had to gather their sons Isaiah, 5, and Jacob, 1, and get them to safety after a tornado and severe storms swept through parts of Nashville and central Tennessee overnight.

"I'm like texting people I know, and I'm like asking my husband if everybody's good," Underwood told Savannah Guthrie and Carson Daly on TODAY. "He said he had to go upstairs at like 2 a.m. and grab the boys and take them down to a little safe room in our house.

"I was like, 'I bet everybody is crying.' It's 2 a.m., freaking out, so it was scary."

At least eight people were killed across four counties, and Tennessee has declared a state of emergency, the Tennessee Emergency Management Agency said.

More than 50,000 people lost power, and Nashville's fire department tweeted that it was responding to reports of 40 structure collapses.

Underwood also spoke about her new health and fitness book, "Find Your Path," as the "Cry Pretty" singer has embraced working out as a stress reliever and a way to recharge herself for her children.

She also has opened up about going too far with cutting calories, revealing she was only eating about 800 calories a day at one point after winning "American Idol."

"I had to start feeling not good physically before I was like, 'Something's not right here,''' she said. "It was a lack of knowledge. It was a lack of knowing how to take care of myself. Kind of going too far the other direction led me to figure out what works because I wasn't feeling good, I wasn't happy."