Torrential rain and gales caused havoc in South Wales and south-west England as the first major storm of the autumn swept in off the Atlantic, causing the death of a 17-year-old girl, flooding homes and leaving the emergency services rescuing stranded drivers from their cars.

The girl was a passenger in a 4x4 driving through a remote forest near the Llyn Briane reservoir, Powys, which hit floodwater, overturned and plunged into a swollen river yesterday afternoon. She and two others were airlifted to hospital with hypothermia but the girl later died.

Winds of 60mph were recorded on headlands around Torbay, Devon and – in South Wales – more than two inches of rain fell yesterday in an area that was also the worst hit by flooding. An inch of rain fell on Bodmin Moor in Cornwall, and flooding badly affected parts of Gloucestershire, where police urged drivers not to venture out.

The number of Environment Agency flood warnings rose steadily throughout yesterday as the storm battered areas already saturated by days of heavy rain and the agency warned last night that the threat of flooding would rise as rainwater drained into river systems.

Last night, the Environment Agency had 141 flood watches and 40 flood warnings in place, mainly in Wales. A severe flood warning was issued for the river Rhymney, at Caerphilly and Bedwas.

Phil Rothwell, head of flood risk at the Environment Agency, told the BBC: "Rivers are rising very rapidly and bursting their banks, also the drainage system that takes the water away from our urban areas is failing." The Environment Agency said it was unable to say how serious the threat of flooding would be until the rain had stopped.

Heavy rain is forecast to head north, and the Met Office issued severe weather warnings for northern England and the East Midlands. Major events over the weekend were called off, including Cardiff Pride, the Jazz in the Park concert in Pontypool and, in Bristol, plans to construct a 26-foot sculpture of the Clifton Suspension Bridge in ice.

In the West Midlands, the Coventry Festival of Motoring and the Dudley Classic Car show were cancelled after the venues became waterlogged.

However, the Bestival music festival in the Isle of Wight went ahead, despite the rain.

As the waters began rising yesterday, the AA reported a surge in the number of breakdowns as drivers tried – and failed – to force their vehicles down flooded roads. The emergency services were inundated with calls as motorists became trapped in their cars. South Wales's fire service received more than 350 flooding calls in a six-hour period.

Roads in Herefordshire and Worcestershire were swamped. West Mercia Police said last night that the main road between Bromyard and Tenbury Wells, which was badly hit by last year's floods, was impassable and the A465 at Stoke Lacy was under two-and-a-half-feet of water.

In the Forest of Dean, drains in Lydney were overwhelmed and 13 houses flooded. Firefighters pumped out water and gave residents sandbags. One, Carol Pritchard, said her home had flooded for the third time in a year, three days after she had a new floor fitted. "It came through the house like a river and caused complete devastation," she said. "It's taken seven months to get everything sorted out after last time and they only finished on Monday. Now we've got to start all over again."

Elsewhere in Gloucestershire, a postwoman, Elizabeth Brain, managed to deliver the mail to all but three of the 320 houses on her round in Westbury-on-Severn. Ms Brain, 23, said: "There were a couple of roads underwater and a couple of houses I couldn't get to because of the flooding. I'll be back out there tomorrow."

In South Wales, a mother and baby were rescued from their home in Ynysboeth, Cynon Valley, after it was threatened by five-feet of floodwater.