More than 100 residents have been evacuated from their homes and transport links cut off after persistent heavy rain caused flooding.
The Water of Ruchill burst its banks, spreading through the village of Comrie, in Perthshire, for about half a mile. Around 70 firefighters have been working all day to remove people from their homes and bring the flooding under control.
Two centres have been set up for those affected. One is in nearby Crieff at the Strathearn Community Campus leisure centre, where people are being given shelter.
A team from the Red Cross have opened a base at Comrie Community Centre - The White Church, where they have helped around 20 residents, including elderly people who have been evacuated from two care homes.
Rab Middlemiss, group manager at Tayside Fire and Rescue, said that about 30 people who had moved out of their homes because of flooding in Comrie in August had again been hit by the severe weather.
"Before they get a chance to get back in, we've had these same properties affected," he said. "Now what we need to look at is how are we going to prevent this happening in the longer term."
Ian Miller, leader of Perth and Kinross Council, said officers had been sent to the site of flooding in Comrie, many of whom would remain overnight.
Properties were also flooded in Dunblane, Aberfoyle and Callander, a spokesman for Central Scotland Fire and Rescue Service said. In Dumfries and Galloway, firefighters were called to a number of flooded homes after the River Cree burst its banks. Houses on Arthur Street in Newton Stewart were being pumped and nine people were rescued from the town's Riverside View, which was completely cut off, said a fire service spokeswoman.
Roads have been closed across regions in central, western and southern Scotland. A landslip shut the A83 in both directions at the Rest and Be Thankful in Argyll for most of the day. It has now reopened. Flooding also closed the A814 in both directions at Rhu, between Helensburgh and Faslane, and high winds meant the Forth Road Bridge was closed to double-decker buses and speed restrictions were in place.
Traffic information company INRIX said heavy rain has led to more than 20 full and partial road closures across the west of Scotland, including the A77 between Girvan and Ballantrae in Ayrshire.