RAF and Navy helicopters had to be scrambled to rescue families stranded by floods in Carlisle.
Police needed boats to mount a rescue mission
Rescuers picked up at least 12 people, including children, from farms and rooftops in Warwick-on-Eden.
Pensioners Wilf and Lorna Johnston told how they watched as water cascaded past their window in Denton Street.
They were alerted about the flooding by a phone call from the Environment Agency early on Saturday. Mrs Johnston said seeing the "water was amazing".
"I picked the phone up at 0300 GMT and received the warning," she said.
"But at first I thought they had jumped the gun a bit, I looked out the window and couldn't see any lights in Denton Street.
"So I went to make Wilf a cup of tea and it was only when I went upstairs and looked out the window that I saw the water cascading from the River Caldew down past the front door - it was amazing seeing all that water."
A spokesman for the Scottish RAF said helicopters had carried out two rescues in the city.
He said: "Both helicopters have carried out rescues from farmhouse roofs and we've been taking people to Carlisle airport.
"The incidents were in the Warwick-on-Eden area, which is right on the banks of the River Eden itself.
"One of the farmhouses had water reaching as high as six feet.
Rescuers row to out to help families trapped by high water
"The situation is already deteriorating and we have taken action at an early stage.
"The Chinook - the national standby emergency helicopter in Hampshire - is ready to be called up if necessary and our rescue teams have been warned."
BBC reporter Mark McAlindon has been in the Stanwix area of Carlisle all day.
He said: "I've been skirting round the edge of this vast, boiling brown flood that made its way through the city from the early hours of the morning.
'Acts of bravery'
"I've seen things I thought I would never see.
"I've seen amazing acts of bravery especially in Eden Terrace and Etterby Terrace where houses are slowing being submerged in water.
"I've seen young men wade and virtually swim with water waist high to rescue women with ladders from upstairs windows.
"I also seen old ladies being carried on shoulders to safety."
Cumbria Police say the A66 has now reopened and that most major roads in the county are "passable", but they are still warning people not to travel unless it is absolutely essential.
Throughout the day officers have received more than 10,000 calls from people affected by the floods.