The water rose quickly, he told CNN, and soon it was at their door.
"We did everything right while the water kept rising and all the appliances went around the house like a washing machine," said Armstrong, who is a crab fisherman.
His wife Lynn was standing in the kitchen cabinets, the only place "your head would touch the roof." he said. Only their heads were above the water.
After hours of waiting in the flooded rescue home, Armstrong's wife succumbed to hypothermia and slipped underwater.
"And then I continued with her, and she just drowned on me," he said, and collapsed.
When the storm finally unleashes devastating possessions in the Bahamas on Tuesday, seven people are known to have died – all in the Abaco Islands, east of Gran Baham – and officials fear the death toll will increase significantly, as more accounts like Armstrong go out.
"She disappeared so quickly," Armstrong said his wife's body was restored.
Armstrong said he then "took a chance" and swam outside the house to his boat, which was moored nearby.
"I saw that my boat was still there, and I was swimming," he said.
Armstrong said he had lived in Freeport for 58 years and had "overcome a lot of hurricanes" but had never seen a flood like that.
"Everything I own is gone," Armstrong said. "Everything."