Winds of up to 70mph have battered parts of the UK as the first severe storms of the autumn hit the country.
97% of power cuts in last year's storms were caused by fallen trees
Wales, Northern Ireland, south-west Scotland and western England are likely to be the worst affected as the storms progress during Friday.
Forecasters say winds could reach 80mph in exposed areas, and have warned of "treacherous" driving conditions.
Several ferry services operating between Wales, Ireland and France have been cancelled.
Heavy rain will accompany the storms, which forecasters say are expected to move inland from the Irish sea coast to the Midlands and northern England.
Gusts of 70mph were recorded in Aberdaron, north-west Wales, during Thursday night.
Winds reached 50mph in Penzance, Cornwall, and 45mph in Plymouth, Devon.
Irish Sea ferry operator Stenaline said the adverse weather conditions had forced it to cancel services due to sail from the Welsh port of Holyhead to Dun Laoghaire in Southern Ireland on Friday.
Early Stena Line services between Fishguard and Rosslare were cancelled, and high speed services between Stranraer and Belfast are to be replaced by conventional ferries.
Irish Ferries also announced cancellations on its Dublin Swift service to and from Holyhead.
Two ferries from Dublin each took an extra two hours to berth at Holyhead on Friday morning in gusty winds of around 60mph.
Five metre waves
A spokesman for Holyhead Coastguard said the way the port was built meant ferries had to turn around and back up to the ramp.
"These are two of the biggest ferries in the world so in high wind that becomes a trickier operation and they take it very slowly."
Five-metre waves have been predicted for Friday morning, said the Marine Control Office at Holyhead.
The weather has forced the closure of Felixstowe Docks until further notice.
There is a 40mph speed limit and alternate lane closures on the Severn Bridge because of strong winds, and a 50mph limit on the second Severn Crossing.
The BBC Weather Centre said on Friday morning there were no flood warnings in place, but the Automobile Association (AA) warned motorists to watch out for flash floods.
Spokesman Colin Hunter said: "Motorists should take great care and consider delaying non-essential journeys in the worst affected areas.
"A 60mph gust creates four times the force of a 30mph wind, and with rain spray and possible
flooding to contend with, driving could be very perilous."
He warned drivers to avoid blowing their car engines by driving too fast through water.
The winds may uproot some trees and cause minor structural damage, said forecasters.
Storms last autumn caused power cuts to thousands of homes, forcing a government review into the chaos.
BBC broadcast meteorologist Helen Willetts said the first storms of the autumn were always a "bit of shock" and that some disruption was inevitable.
In the severe storms of last October, power firms were criticised for mass power cuts.
Falling trees were responsible for 97% of the cuts.