The UK is blanketed by "unusual" danger-to-life wind warnings ahead of Storm Isha, with people warned not to travel amid possible 140km/ph gusts.
Rail, sea and air travellers were hit with disruption across the UK today, with closures, cancellations and delays expected across a number of services.
Damage to homes and buildings, falling trees, power cuts, flying debris, large waves and even some flooding in places should also be expected, forecasters warned.
Winds of 127km/ph were recorded in Capel Curig, Wales, in the early afternoon.
Agencies across Cumbria have declared themselves on standby for a major incident, while elsewhere a person was hit by debris in Belfast.
Sellafield nuclear site in Cumbria was closed due to the storm.
It said in a statement: "Owing to severe weather warnings related to Storm Isha, operations at Sellafield have been suspended.
"This is a precautionary step which allows us to safely shut down our operational plants to prepare for predicted worsening weather conditions this evening.
"We have also sent some people home early so that they could travel before the weather conditions worsened.
"Operations are expected to resume tomorrow and employees are currently advised to attend work as normal."
Met Office meteorologist Tom Morgan said: "We're expecting widespread gales to affect the UK, amber warnings are in place for large parts of the country.
"There's the potential for danger-to-life and damaging winds potentially leading to some power cuts in places, some large waves around coastal regions could bring some debris onto roads and trees could come down."
He added: "We have a wind warning in place across the whole of the UK, it's pretty unusual for the whole of the country to be under a blanket wind warning."
The Met Office has said "everybody" across the UK will be affected by the storm.
Two different amber warnings are in place across most of the UK from 6pm to tomorrow morning, saying 112km/ph winds should be expected inland, with gusts of 128km/ph on coastal regions.
In parts of Scotland, northern England and Northern Ireland winds could reach 144km/ph.
A yellow wind warning also covers the UK, including parts of London and the south-east, while four rain alerts were in place around the country.
Nearly 10cm of rain could fall over a few hours in some regions and cause localised flooding, with nine flood warnings already in place across England.
Network Rail said 80km/ph speed restrictions have been imposed across most routes to keep passengers and trains safe from falling trees and debris blown onto tracks, with disruption likely to continue into tomorrow morning.
Scotland's railway operator cancelled all of its services after 7pm and there will also be no morning rush-hour services tomorrow.
A number of rail services across the country warned against travel, while air traffic control restrictions were in place, leading to some flight cancellations.
National Air Traffic Services (Nats) told PA: "Due to adverse weather conditions across the UK, temporary air traffic restrictions are in place. Restrictions of this sort are only every applied to maintain safety.
"Our teams are working closely with airports and airlines to minimise disruption. Passengers should check the status of their flight with their airline."
British Airways said: "Like other airlines, we have had to make schedule adjustments due to the adverse weather conditions across the UK and Europe caused by Storm Isha.
"We've apologised to our customers for the disruption to their travel plans and our teams are working hard to get them on their way as quickly as possible."
Ferry company Wightlink also warned of potential disruption, while the RAC warned drivers to lower their speeds and even consider delaying journeys.
The warning comes as Met Éireann issued a Status Red wind warning for counties Galway, Mayo and Donegal.
The warning for Galway and Mayo lifted at 9pm while the alert for Donegal is valid until 1am.
