Weather bomb: Two people swept into sea at Portstewart as storm batters north coast
Scroll down for live coverage from our journalists at the north coast, plus pictures, video, tweets and Met Office updates
Two people were swept into the sea at Portstewart on Wednesday as a so-called "weather bomb" battered the north coast.
The jogger and dog walker were on the beach when the "unusually high" waves swept them out - and they luckily managed to scramble to safety.
"Just witnessed a second person get washed away and only just escape to safety," said the National Trust's Portstewart Strand Twitter feed.
"We can not stress this enough. PLEASE STAY AWAY FROM THE BEACH."
Severe gales of up to 81mph have been recorded as the rapid cyclogenesis - a deep low pressure system known colloquially as a weather bomb - moves slowly eastwards between Scotland and Iceland.
Waves 45 ft high were recorded off the Donegal coast at midday.
Beaches and seafronts at Benone, Portstewart, Ballintoy and Ballycastle all flooded and safety warnings have been issued to keep members of the public away.
The playpark at Portstewart was completely submerged under water on Wednesday morning.
The Met Office has an amber warning of wind in place for the north coast, and a yellow warning across the whole province, until Thursday morning.
All ferries between Belfast and Cairnryan were cancelled after a ferry collided with part of the south west Scotland terminal on Tuesday.
Sailings between the Dumfries and Galloway port and Belfast were suspended to allow the ship to be examined, the BBC reported.
Stena Line said there were no injuries and all passengers and crew disembarked as normal.
School bus hits tree
In the Republic of Ireland, 11 schoolchildren escaped injury when their minibus struck a falling tree on Wednesday. The quick-thinking actions of the bus driver meant that serious injury was avoided in the incident in Letterkenny.
Gardai say he saw the tree falling and managed to brake, meaning only the front end of the bus took the impact.
There were eleven primary school children, aged from 4 to 11, on the minibus when the incident happened in the Lisnennan area of the Donegal town.
More than 180 homes in the Portnoo area of west Donegal were meanwhile without power.
Gusts of 70mph have been recorded on the Forth and Tay road bridges in Scotland.
"Waves will be unusually high, bringing the risk of localised flooding of roads and causeways, particularly in western and northern Scotland and northern coasts of Northern Ireland," said the Met Office's Chief Forecaster.
He also warned of snow on the hills: "Frequent wintry showers will also bring an additional hazard, mainly over higher ground. The public should be aware of the potential for disruption to travel and perhaps also power supplies."
All main roads were salted early on Wednesday morning but drivers have been warned to exercise caution, particularly on untreated routes.
In County Tyrone, the B50 Gillgooley Road was closed just outside Omagh on the Drumquin side of Gillygooley Primary School following a traffic collision.
Northern Ireland Electricity warned of possible damage to the electricity network, especially in exposed northern locations.
Emergency crews, engineers and call handlers are on stand-by.
John Wylie, from the Met Office in Northern Ireland, said: "We'll be looking at gusts of 50-60mph for most of us, but it's the north coast that we're most concerned about and our amber warning is valid for northern coastal fringes, including Rathlin.
"We could see gusts of around 70mph and that's the sort of wind speeds that can topple a few trees and bring some interruptions to power supplies on a localised basis.
"We normally get three, four or five occasions between about December and March where we would be expecting those sort of wind speeds across the bulk of Northern Ireland. It's probably just one of those days you need to hold the steering wheel that little bit tighter and keep a wary eye out for any weather obstacles.
Mr Wylie added: "There will be some snow, yes, a wintry element to the showers as they blow through but most of the snow will be on high ground, we could see two to five centimetres on ground above 600 or 700 feet, but that's pretty normal for this time of year."
Temperatures are actually not much colder than usual for this time of year, according to Meteogroup forecaster George Goodfellow - but the brisk winds will bring a distinctive chill to the air.
"We are looking at highs of up to 12 degrees in some western areas today, and even 10 degrees in the South East (of England) tomorrow, but the strong winds will make it feel fairly nasty," he said.
Temperatures will be around 4 to 5 degrees celsius in Belfast on Wednesday and Thursday.
A second storm is due to roll in from the Atlantic Ocean on Friday.
In response to whether we'll see a white a Christmas, Mr Wylie said: "It's still two weeks away, it's up in the air.
"At the moment the weather could do almost anything in two weeks' time. There's alternating spells of mild and cold weather so it's just a question of what air mass is in place on the big day itself. Too soon to say."
- If you lose your electricity supply contact the NIE Customer Helpline on 03457 643 643 or report the fault online at nie.co.uk.
Scotland Western Isles without power
A gust of 81mph was recorded in Tiree at 10am while South Uist was hit by a 79mph gust at 9am and Islay by a 77mph wind at 5am, according to the Met Office.
Winds of around 50mph have been recorded in north-west England and North Wales, where yellow "be aware" warnings are in place.
The whole of the Western Isles was left without power after an outage just before 7am.
Scottish Hydro Electric Power Distribution said its engineers were working to restore supplies to the 17,500 customers affected.
Elsewhere, a rescue operation was launched to help a fishing vessel which issued a Mayday call at around 5.30am after it was hit by a wave that smashed windows on the bridge.
The Shetland Coastguard rescue helicopter and Stromness Lifeboat were sent to the scene off Orkney.
The lifeboat is escorting the British-registered vessel, which has a Spanish crew, to Westray in Orkney. None of the 16 crew are thought to be injured.
In Aberdeenshire around 20 cars were freed after they were stuck in icy conditions at Cairn O'Mount, while the Forth Road Bridge was closed to high-sided vehicles and the Tay Bridge was only open to cars.
Fifteen flood warnings and 12 flood alerts have been issued by the Scottish Environment Protection Agency (Sepa).
Many ferry services operated by Caledonian MacBrayne, which operates in the west of Scotland, have been cancelled or disrupted while the Argyll Ferries service between Gourock and Dunoon has been suspended.
There were also disruptions and cancellations on NorthLink Ferries services between Orkney, Shetland and the mainland, while P&O said its Larne and Cairnryan sailings were operating with delays of up to at least two hours, with disruption expected throughout the day.
Several train services will be cancelled as a safety precaution, Network Rail and train operator ScotRail announced.
Western Isles Council said all its schools and nurseries will be closed as police have advised the public not to travel unless it is absolutely necessary.
All depots, libraries, museums and sports facilities in the Western Isles are also shut.
Several schools and nurseries in the Highland Council area have been closed.
Scotland's Deputy First Minister John Swinney told BBC Radio Scotland: "It is important to keep this in context.
"It's not a surprise that Scotland faces severe winter weather, we face it to a greater or lesser extent every year. This morning we're wrestling with a number of different issues."
He added: "I think it's important to remember that this is weather which is characteristic of winter weather in Scotland and what's important is that we take the necessary steps to prepare for it.
"That involves the public authorities preparing for it but also members of the public being aware of the circumstances as well."
Councils south of the border insisted they are prepared for the plunge in temperatures, with gritters "out in force" and depots filled with about 1.3 million tonnes of salt.
Belfast Telegraph Digital