A lorry driver has died and people are being evacuated from their homes as ferocious winds sweep the country.
Police said the driver died when his HGV toppled on to a number of cars on the A801 in West Lothian as the g ale-force winds brought widespread disruption to the transport network.
Hundreds of homes in Norfolk and Essex are being evacuated after officials warned that the lives of people in the region could be at risk from the worst coastal tidal surge for over 60 years.
And tens of thousands of properties across the country have been hit by power cuts as winds of up to 140mph battered powerlines.
Northern Powergrid said that 55,000 homes have been affected since midnight and 25,000 properties in the North East, Yorkshire and North Lincolnshire are still without power.
The Met Office said there had been severe gales of between 60mph and 80mph across Scotland and northern parts of England, and some mountainous regions in Aberdeenshire and Inverness-shire reported speeds of around 140mph.
The Environment Agency (EA) has issued a number of severe flood warnings - the highest cat egory, warning of danger to life - to the east coast and north Wales as high tides and strong winds threatened to swamp the coastline.
Officials said that 6,000 homes could be flooded in the "worst case scenario".
Almost 700 homes are being evacuated in Norfolk as local officials attempt to stem the damage from the coastal surge.
Residents in some parts of Great Yarmouth and the north Norfolk coast are being urged to leave their homes ahead of the high tides that are expected over the next two days.
Local officials are setting up emergency accommodation facilities and are handing out sandbags to help people protect their homes, police said.
Some residents of the seaside town of Jaywick, near Clacton, in Essex are also being evacuated , Essex police said.
Police in Humberside have declared an emergency situation as they prepared for coastal surges from this evening.
So far the EA has issued more than 250 flood alerts across England and Wales, including 28 severe flood warnings which are only issued when flooding poses a "significant threat to life".
The agency said communities along the North Sea coast from Northumberland to the Thames Estuary and Kent, in addition to those on the Irish Sea coast from Cumbria down to Cheshire, could see significant coastal flooding later today and into Friday.
A spokesman said in some areas sea levels could be higher than those during the devastating floods of 1953, but defences built since then - including the Thames and Hull barriers - mean that many parts of the country are much better protected.
However, some coastal flood defences could be " overtopped" by the combined effect of high tides, high winds and a large tidal surge, he said.
Anne Edwards, editor of the Great Yarmouth Mercury, was one of those told to leave their homes, but is determined to ride out the storm with sandbags and supplies.
She was awoken by an alert call from the Environment Agency at 6.30am, warning of severe flooding in the area of her home, which is a mile from the coast.
Ms Edwards, who believes hundreds of homes are being evacuated, said: "We're staying put. The house we live in was flooded in 1953 and there's a four-and-a-half foot-high water line in the dining room from then. We always knew we might be at risk of flooding, so there is a camping stove upstairs and we have water and cans of food.
"I'm going to get the paper out then go home for dinner, but then I'll be back in the office later. I've got my wellies ready."
The weather has also caused chaos to the rail network, with services for the entire of Scotland and parts of the north of England suspended.
This morning trains were halted at their nearest stations and passengers told to disembark after Network Rail said debris on lines and damage to equipment meant it was not safe to operate any services.
A number of flights have also been disrupted by the bad weather.
Closures, fallen trees, minor accidents and incidents of flash flooding are affecting the road network in parts of the country.
This morning Environment Secretary Owen Paterson chaired a meeting of the Government's emergency Cobra committee to discuss the response to the storm.
:: People are being urged to check the Environment Agency website or follow @EnvAgency and #floodaware on Twitter for the latest updates on flood warnings.