"One window broke and I knew," she said. "And I said to myself, 'Oh my Lord. My house is going down."
Falling bricks from the house had broken seven of her ribs and punctured her lungs.
Beneath her bleeding body, her children - her 8-year-old son, Domonick, and her 5-year-old daughter, Reese - were unscathed, and breathless. She sent them scampering for help.
Alone in the dark she recorded her last will and testament on her phone.
But her children found help. Rescuers arrived. They put tourniquets on her nearly severed legs.
That was March 2, 2012. There were 140 reported twisters, 76 confirmed landings and 39 deaths.
Hours later doctors amputated her legs. Decker vowed she'd fight on. And so began a grueling year-long rehabilitation, hundreds of hours spent in the gym, and a fitting for a $100,000 of prosthetics.
"This is just a new way of living," she told ABC News. "If the worst thing that ever happened is me losing my legs, I'm good."
"I wanted to stand up and I wanted to walk," she said. "I couldn't get those legs fast enough. … Four to five hours I can spend on these legs, and that's an equivalent to about 16 hours on your legs."
Last week, she marched into the Kentucky Senate to fight for a bill that would require insurance companies to cover new and refurbished prosthetics.
Currently, nearly 2 million Americans are amputees fitted with prosthetics.
According to a study by Johns Hopkins and the Amputee Coalition, insurance companies are only required to pay for the refurbished prosthetics and refitting in 20 states.
The Kentucky Senate plans to hold more hearings this summer on the bill.
In the meantime, though, Decker said she advocates a national bill.
"This is what I was meant to do and I'm excited about that," she said. "I'm excited that something from a bad situation we can make something really good."