Police and local people have spoken of the treacherous conditions on the day a teenage girl died off a flooded road.
The 17-year-old died after a 4x4 car left a flooded forestry track and overturned into a river in Powys.
A man in the vehicle had to walk several miles to a farm to raise the alarm after Friday's incident near the Llyn Brianne reservoir.
The teenager who died was a tourist from Thamesmead in south London. Her family have been informed.
She was airlifted to Bronglais Hospital, Aberystwyth, along with a male and another female with hypothermia.
Dyfed-Powys Police have not released the dead girl's name at this time at her family's request.
Three helicopters were used in Friday's rescue on a remote forestry track north of Llyn Brianne reservoir, near the Ceredigion border.
Insp Robert Price, of Dyfed-Powys Police, said that flood water from the river had caused the vehicle to "lose its footing" and tip into the river.
Inspector Eric Evans told BBC Radio Wales later: "A man in the vehicle had to walk some distance in miles from the scene to the nearest property to raise the alarm.
"The weather conditions were extremely bad and it took him a long time. He must have been quite traumatised by his journey."
Gary Smith, who was part of a group off-roading for the weekend and had camped in the area, said he and his friends came across the 4x4 vehicle on Saturday morning.
He said yesterday's weather conditions were bad.
He said: "It never stopped raining from the minute we woke up yesterday morning until we got here last night and set up camp.
"The rivers were gushing like mad - you can't get any more water down there than what there is."
Simon Carrington, who lives locally, said: "It had been raining constantly and the rivers were swollen, it was really high.
"First of all I saw saw a fire engine arrive after I picked the children up from school, it was about probably 3.30pm-4 o'clock.
"I think it was an air ambulance helicopter that came in and then half-an-hour later there was a RAF helicoper - there was a lot going on there 'til dark - eight o'clock in the evening.
"We tried to drive to Llanwrtyd Wells over three fords, it (the water) was at least a metre above the river level - it was really extreme it just came up in no time but it soon drops down again.
"It is really tragic, you have to be really careful in this weather, it is really extreme."
Environment Minister Jane Davidson said her thoughts were with those affected by the flooding.
"In particular I would like to express my deepest sympathy to the family of the young woman who tragically died in an accident in Powys on Friday evening".