Britain placed the army on standby Thursday and many schools were to close as forecasters issued a rare "red weather" alert for an approaching storm, warning of "danger to life" from fearsome winds.
Storm Eunice is expected to make landfall in southwest England Friday morning after barrelling its way across the Atlantic, packing gusts of up to 160 kilometres per hour.
The warning comes as separate storms killed at least four people and caused widespread travel disruption in central Europe on Thursday.
Prince Charles, the heir to the throne, has postponed a Friday trip to South Wales "in the interests of public safety", his office said, and transport operators said all trains in Wales had been cancelled for the day.
The red weather warning, effective from 0700 GMT on Friday, covers the northern coastline of Devon, Cornwall and Somerset in southwest England, as well as the south coast of Wales.
Schools in the affected region of England and Wales announced they would shut for the day, and residents were urged to remain indoors. Heavy snow was also forecast in Scotland and northern England.
Eunice is expected to cause "significant disruption and dangerous conditions due to extremely strong winds", the Met Office said.
It said there was a risk of "flying debris resulting in danger to life" and "damage to buildings and homes, with roofs blown off and power lines brought down".
Ireland's meteorological office also issued an alert for the storm, warning of "severe and damaging winds" and the possibility of coastal flooding in the south.
Another less severe storm, Dudley, caused transport disruption and power outages when it hit Britain on Wednesday, although damage was not widespread.
The UK government on Thursday held a meeting of its emergency "COBR" committee to discuss the response to the two storms.
Prime Minister Boris Johnson expressed sympathy for thousands of residents left without power in northern England by Dudley.
Asked about further support ahead of the arrival of Eunice, he told reporters that "the army is on standby".
Transport companies warned that roads, bridges and railway lines were also likely to be closed, and airports would suffer delays and cancellations.
In England, some rail passengers have already been urged by train operators not to travel on Friday.