Seven severe flood warnings - deemed a threat to life - remain on the River Don in South Yorkshire.
One man told the BBC he carried children from his gym in Rotherham, wading through water that had submerged the streets outside.
"The woman was reported as having been swept away by flood water in Rowsley and the body of what is believed to be the same woman was found in Darley Dale", police said in a statement.
The Environment Agency reduced its number of flood warnings - meaning flooding is expected - to below the 60 mark on Friday afternoon, with forecasters predicting the worst of the rain had been and gone.
Dozens of people were forced to spend Thursday night at Meadowhall shopping centre near Sheffield, after roads flooded and water from River Don poured over the top of defences completed past year at a cost of more than £20 million.
The Environment Agency said river levels peaked in Sheffield and Rotherham overnight, and are starting to fall, although they are still high in the Doncaster area, with further flood impacts anticipated over the coming 24 hours as water travels downstream.
Toll Bar Post Office worker Kathleen Overton, 61, told the PA news agency: "It was nearly biblical, I would say".
There was gridlock at Sheffield's Meadowhall Shopping Centre, also flooded in 2007, after it cancelled its Christmas Live event which was expected to be attended by thousands of people on Thursday evening.
"Residents in these areas are advised to evacuate immediately", Doncaster Council said.
The Met office said that "there were a lot of other places that had 80mm or more, especially in Yorkshire".
The torrential rain also brought widespread travel disruption with some rail operators issuing a "do not travel" advice to passengers in places around Sheffield and other affected areas while many roads were also closed. They have put in minimal flood defences.