A record wind speed of 114mph has been recorded in Ireland as Storm Eowyn causes widespread disruption on both sides of the Irish Sea.
Red warnings for wind cover the entirety of Ireland and parts of Scotland as the storm brings staggering winds that pose a danger to life.
Trains and flights across the UK face cancellation or disruption on Friday, while schools in Northern Ireland and central and southern Scotland have been urged to shut.
Follow the latest updates on Storm Eowyn
An “unprecedented” number of homes in Ireland have already lost power, with electricity provider ESB Networks telling Sky News the storm had affected 560,000 homes, farms and businesses by 6am – a huge number so early on in this weather event.
In Northern Ireland, more than 93,000 homes and businesses are currently without power, NIE Networks has said, as the storm was causing “widespread damage” to the electricity network.
A statement said: “We anticipate we will begin assessing the damage to the network after 2pm once the red weather warning has been lifted.”
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In Scotland, Tesco has announced the closure of its stores in the red danger to life zone covering millions of people across Glasgow and Edinburgh.
Besides the red wind warnings, yellow ones are in place for the whole of the UK, while for northern England and northwest Wales an amber warning for wind from 6am until 9pm is in place.
A yellow rain warning is in place for the coasts in the south of England and Wales till 9am.
A string of public authorities have issued statements warning the public to travel only if absolutely necessary.
Around 4.5 million people in parts of Northern Ireland and Scotland were sent an emergency alert on their mobile phones on Thursday evening.
Multiple flights at airports in Glasgow, Edinburgh, Manchester, Newcastle, Liverpool and Dublin were cancelled.
National Rail has said a “do not travel message has been issued from multiple train operators” as it advised passengers to check for travel advice before travelling.
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Some health services have also been suspended, with NHS Lothian cancelling all routine, non-urgent planned procedures on Friday and postponing the majority of hospital outpatient appointments to protect patients and staff.
NHS Lanarkshire has also postponed all non-urgent appointments in hospital and community settings.
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