A Royal National Lifeboat crew was airlifted to safety after becoming trapped while helping to rescue a disabled man from a flooded caravan.
Residents said the community had pulled together, providing food and shelter to the vulnerable.
Jenny Evans, 42, of Stafford, who owns a caravan at the Beachside Caravan Park, said: "One of our neighbours, who is known as Nana Dot, had to be rescued from her static caravan. She is in her mid-70s and had to be taken in the back of a pick-up truck.
"I've seen it flood before but nothing as bad as this. It's like we've had a month's worth of rain in 36 hours."
Twenty-five homes in the nearby village of Talybont were evacuated in the early hours.
Ellen ap Gwynne, the council leader for the area, said: "Many people's homes have been ruined - some worse than others - so it won't be cleared up overnight, but we'll be working towards that."
Meanwhile, footage filmed on board RAF rescue helicopters showed just how treacherous the rising waters had become. Winch crews were shown lifting people from a home that appeared to be almost submerged.
A spokesman for Environment Agency Wales said five flood warnings were now in place. "We have seen up to five inches of rainfall in 24 hours in this area."
Meteorologists have put the unseasonably bad weather down to the jet stream moving in an abnormal direction. Jet streams are a zone of fast-moving winds typically flowing around the globe about 10km above the Earth's surface.
At this time of year the Atlantic jet stream would normally take a path past the northwest of Scotland, bringing rain to the northwest and drier weather to the southeast.
However, this northern summer it is getting stuck in across southern England, bringing with it low-pressure systems that have resulted in the wettest April on record and a miserable June.
Reid Morrison, a Met Office forecaster, said: "The jet stream is heading towards Spain and the Biscay area, further south than usual, so we are in the track for areas of low pressure streaming in from the Atlantic - which is the cause of the bad weather."
- INDEPENDENT