Heavy rain and winds as high as 100mph (160kph) are battering parts of the UK, causing floods and disrupting travel.
Homes and businesses were evacuated and hundreds have been left without power.
Gales have been reported on the Welsh coastline with even stronger winds reported inland,
The Met Office has warned there is worse to come.
There are also nearly 200 alerts for possible flooding in England and Wales.
Amber "be prepared" warnings for heavy rain have also been issued across much of south Wales, and in south-west England where a joint command structure has been set up by rescue services.
In Scotland, the warnings for expected flooding also cover the Borders and Dumfries and Galloway - as rainwater filters down from the hills.
An amber warning for heavy rain was issued for much of Strathclyde, Dumfries & Galloway, Stirling, Perth & Kinross and the southern Highlands. And the River Nith in Dumfries is flooding for the second time in a week.
In other developments:
- Emergency crews sealed off part of Exeter after a 20ft wall collapsed. A police sniffer dog is involved in searching for anyone trapped under it, but there are no reports of any people involved so far
- In Dumfries and Galloway about 500 homes lost power after lightning strikes, and the mobile phone network is also affected
- In Birmingham, strong winds blew a mosque roof into the road, damaging three cars in Evelyn Road, Sparkhill
- In Carmarthenshire, a woman motorist was rescued after her car was swept 100 metres along a fast-flowing, swollen river near St Clears
- In west Wales five people were taken to hospital after a Peugeot 206 was flipped over by high winds on an exposed road at Milford Haven
- In Wollaston, in the West Midlands, a teenage girl was left with serious head injuries after being hit by a branch from a falling tree
- Twenty homes were evacuated after water breached the 200-year-old Grand Western Canal at Halberton, Devon
- In Ulverston, Cumbria, a hospice was evacuated after a nearby stream burst its banks, flooding bedrooms and offices
- Three centres have been opened at Llandudno, Caernarfon and Bangor in north Wales to provide shelter for those affected by flooding
The Met Office says the wet and windy weather will move east across England and Wales overnight, leading to clearer conditions in most areas. But rain will continue to affect the south-east and north-west of the UK into Friday morning.
But the Environment Agency warned rain falling on already saturated ground could lead to further river and surface water flooding.
John Curtin, head of incident management, said: "We ask that people stay safe by staying away from swollen rivers and not attempting to drive through flood water."
Wind speeds have risen in north-west Wales and gusts of 70mph have been recorded at Capel Curig.
Unofficial wind speeds of 100mph have also been recorded on Snowdon, Gwynedd, and 92mph at Worm's Head on the Gower peninsula.
In Wales a fallen oak tree narrowly missed a house in New Quay, Cardigan Bay, where a "massive crash" was heard at 05:30 GMT.
In Northamptonshire about 1,000 people had to leave their holiday homes at Billing Aquadrome, alongside the River Nene.
On the railways, services between Devon and Somerset were badly affected with the worst flooding impact for five years.
Twelve separate areas of track were impassable and the line was likely to be closed for the next two days, said a First Great Western spokesman.
Arriva Trains Wales said all services in north Wales were either cancelled or delayed due to flooding between Holyhead and Llandudno Junction.
In Cumbria, TransPennine Express said it could not operate any train services to or from Barrow because of "severe" weather conditions.
BBC trainee Ross McCoughlin, 23, has been staying at the Northwick Hotel in Evesham, Worcestershire, and said floodwater meant guests were "stuck".
He said: "When I came down to breakfast the road was gone and it's now a river. It was quite a shock seeing ducks coming up to the front door."
In Kent, the RSPCA criticised a decision to allow hundreds of sheep to travel on a ship which had to turn around due to bad weather.
The ship, the Joline, had to return to the port of Ramsgate, and as the animals were taken off in two lorries they were greeted by angry protesters who condemned the decision to sail amid concern for the animals.
A canoeist had a narrow escape after being caught in bad weather near Burgh Island, off the south Devon coast.
Dave Scullion, watch manager at Brixham Coastguard, said: "We strongly advise not to go out in these stormy conditions, particularly in small craft such as canoes or kayaks.
"Sending units to rescue people in these types of avoidable incidents will put the rescue teams at risk."