Dreamland's Scenic Railway rollercoaster has collapsed in high winds.
Pictures from the scene show sections of the iconic Margate landmark - currently under reconstruction - almost completely obliterated by last night's storms.
Strong gusts battered east Kent during the early hours and it is believed parts of the fragile wooden structure came down at around 4am.
Jason Evans, owner of the Lobster Van Hire outlet on Belgrave Road which overlooks the Scenic Railway, took these pictures of the damage.
He said: "I arrived at 7am and, though it was still dark, I noticed the skyline was different.
"Something was missing. When it got lighter I realised the extent of the damage. I'd say they'd rebuilt about half of the structure, and two thirds of that has come down.
"They'd built one of the corners and part of the dipper, and that's gone."
Emergency engineers were on site this morning inspecting the damage, together with Thanet council leader Iris Johnston.
Cllr Johnston tried to play down the damage, saying: "It's only a small section - the main part is fine.
"The photos only show part of the structure."
Built in 1920, the Scenic Railway was Britain's oldest surviving rollercoaster.
It fell into disrepair when the attraction closed in 2005 and was then badly damaged by an arson attack in 2008.
Refurbishment of the Grade II* listed ride - led by designer Wayne Hemingway - is part of an £18m project to reopen the amusement park in 2015.
The Scenic Railway had been painstakingly dismantled over 10 months and was in the process of being rebuilt.
Most of the funding has been granted by the Department for Culture Media and Sport's Sea Change programme, the Heritage Lottery Fund and the council.
Mr Hemingway told the BBC in September: "The Scenic Railway is the kind of thing that people will shed a tear over when it starts to run again.
"You have to pinch yourself sometimes because there were times when we were thinking this project seemed to be going round and round in circles.
"But finally the community won and it feels like the battle is over but the journey is just beginning."
Cllr Michael Tomlinson, who worked at Dreamland from the late 1960s to the 1980s, said the collapse could be a setback for the revamping of the site.
"It sounds as if the majority of the damage occured at one of the bend sections. We'll have to see of this holds up the 2015 opening," he said.
But Cllr Johnston suggested the collapse would not affect the opening date.
"I've spoken with the contractors and they're confident this will not be a setback," she said.
The funfair site, once home to Europe's largest big wheel, was compulsory purchased by Thanet District Council in 2013 after an order granted by the government.
Vintage fairground rides from around the UK are being restored and re-created for the new fun park, which will be run by the Dreamland Trust, as well as classic sideshows, vintage cafes, restaurants and gardens.