Flooding has caused scores of homes to be evacuated, roads and schools to be closed and rail services to be cancelled in South Yorkshire.
Police said they had received more than 200 calls from Sheffield, Rotherham and Barnsley caused by heavy rain.
Dozens of roads were closed because of flooding up to 3ft (91cm) deep.
In one incident, a man was stuck in his car when water came up to its bonnet under a bridge in Fife Street, in Sheffield's Wincobank area.
Northern Rail said flooding near Elsecar was affecting the line between Meadowhall and Barnsley.
Householders were using sandbags to stop the water entering their properties in areas such as Mill Road, Ecclesfield.
Dave Newton sent BBC News Online pictures of Chapeltown flooding
Police said the River Dove had burst its banks at Station Road in Worsborough, and they were expecting similar problems with the River Don.
The road leading up junction 35 of the M1 in Chapeltown, in Sheffield, was also flooded.
Officers urged motorists not to travel unless their journey was vital.
A fire service spokeswoman said: "One caller just rang to say the water was now at the top step of his cellar. He was obviously concerned.
"We've had a very busy night across the area."