A helicopter pilot who rescued 17 people stranded by rising floodwaters in the United States says he had earlier prayed to God to show him his life had meaning.

Nashville-based Joel Boyers said days later he had received a phone call from a desperate woman looking for someone to help her brother and his family who were stranded on a rooftop in Waverly, Tennessee.

According to Associated Press, Mr Boyers was piloting the only helicopter in the area at the time and manoeuvred around power lines, balanced on sloped rooftops and hovered over floodwaters to rescue 17 people in total.

Speaking about Saturday's incident in an interview with the Associated Press, Mr Boyers said it felt great to use his skills for something so important :

"As soon as I popped over the ridge, it was nothing but tan raging water below me," he said.

"There were two houses that were on fire. There were cars in trees. There was tonnes of debris. I knew no-one was going to be able to swim in that."

A few people were out in boats, rescuing the stranded, and one person was helping with a jet ski, but Mr Boyers was alone in the sky. He started flying up and down the flooded creek, grabbing anyone he could :

"I literally prayed just days before this that God would give me some meaning in my life, and then I end up getting this call," he said.

At least 22 people were killed and dozens are still missing after last Saturday's flooding, with more than 270 homes destroyed.