Large swathes of the UK were warned of the risk of floods as the Met Office forecast heavy rainfall for south and south-east England on Tuesday.
Three severe — or “danger to life” — flood warnings were in place in Dorset, along with 100 or so lesser warnings in England, Scotland and Wales.
A night of rain and exceptionally high tides overwhelmed defences in Dorset, with Chiswell’s flood siren sounded.
One English Channel coastguard said she had never seen such a prolonged storm.
Karen Bosman, watch officer at Solent coastguard, also told the BBC there were forecasts for more high winds of up to 50mph on Tuesday that would whip up the sea.
As the sea came over the defences at Chiswell last night the sirens sounded and local residents gathered their family members, pets and belongings and moved to the upstairs floors of their homes.
The Heights Hotel also opened its doors as a place of refuge for those needing to move to higher ground.
The causeway, which links the Weymouth mainland to Portland, was closed overnight because of tidal flooding.
A spectacular display of lightning lit up the sky among ferocious waves and strong winds this morning, with the full effect of nature’s storm last night clear for all to see.
Pom Pom — a rock stack just off the coast — has been partially wiped out and Chesil Beach completely flattened — its profile has been totally changed.
Places like the Cove House Inn pub near the sea wall are now very exposed during high tide, BBC reported.
Last night, one wave actually hit the pub. Luckily the shutters were closed but some water did get in, so there is concern for what lies on the horizon.
A clean-up operation is under way in Aberystwyth after storms battered the coastal town on Monday night.
The 250 people who were evacuated from their seafront homes have also now been told they can return.
In Dorset, the Environment Agency set off the flood siren at about 22:00 GMT to warn of extreme danger to people and property after waves crashed over defences at Chesil Beach, near the village of Chiswell on the Isle of Portland.
Dorset Police told families in the area to move to upstairs rooms facing away from the sea.
Other areas affected included some Somerset villages which were cut off; Cornwall, where waves of up to 27ft (8m) were recorded and some properties flooded and Salisbury in Wiltshire, where some residents had to leave their homes.