The incident happened in Antrim on Friday as police closed the road in both directions.
Gusts of nearly 100 mph have been reported in some areas – and the Met Office says speeds reached 98 mph at Brizlee Wood in Northumberland.
A rare, red ‘life threatening’ weather warning expired in the early hours of this morning – but orange and yellow wind warnings remain in place over large areas of the UK.
The orange warnings covering the north-eastern coasts of England and Scotland, and the south-western coasts of England and Wales, will expire at 9 a.m. this morning. Another yellow warning applies to most of the UK until 6 p.m. tonight.
Britons are still advised to travel only when absolutely necessary, with the Met Office calling night gusts “damaging”.
Roads were closed by fallen debris in the worst affected areas of Scotland, while LNER rail services north of Newcastle were also disrupted, with high winds, heavy rain and snowfall arriving from Friday afternoon.
Cold weather is expected in the North East, North West, Yorkshire, West Midlands and East Midlands through Monday.
Friday night’s Premiership rugby match between the Newcastle Falcons and the Worcester Warriors has been postponed until Saturday night due to security concerns.
And in North Wales, ITV has abandoned plans for a live episode of I’m A Celebrity… Get Me Out Of Here! from Gwrych Castle – with Ant and Dec pre-recording their parts of the program instead.
The Merseyside Fire and Rescue Service said it had faced a “large” number of incidents, including “fallen trees and roofs torn from structures”.
Northern Powergrid said strong gales caused blackouts for more than 55,000 customers, mainly in Northumberland, County Durham and Tyne and Wear areas.
And Northwest Highway police said about 120 trucks were “stuck in the snow” on the M62 at junctions 21 and 22 and urged motorists to avoid the area.
Tweeting photos of the highway covered in white, they said snowplows had been deployed.
A Met Office statement said: “People should stay away from the coast as waves and debris are life threatening. “
Arwen is the first named storm of the 2021/2022 season – which started in September.
He is expected to cross the North Sea and enter Europe by Sunday.