A major part of Brighton's ruined West Pier has collapsed after being battered by winds of up to 70mph and rough seas.
A number of its main supports on the eastern side appear to have been washed away, splitting the former pavilion into two sections.
The pier, which is not maintained and was shut in 1975 after being deemed unsafe, burnt down in 2003.
On Tuesday, Brighton's Seatown Rockers tweeted "The West Pier is going. Lost a significant part of supporting legs."
'It's very sad'
Part of the derelict Grade I listed pier's eastern side crumbled into the sea in January 2013, following cold weather conditions.
Solent Coastguard has urged people to stay away from the shoreline and coastal structures such as piers and sea walls during the stormy weather.
The blackened frame has become a much photographed Brighton landmark.
Rachel Clark, chief executive of the West Pier Trust, which owns the structure, said: "There have been collapses for several weeks as we've had the high winds, but this is more significant and obvious.
"A significant section of the pavilion island skeleton has collapsed. It's very sad but it was always going to happen.
"It's not being maintained so eventually the elements are going to take their toll and they have again this time, but much more significantly."
'Roof flapping away'
A main road has been closed in St Leonards after the roof of a four-story block of flats on the A259 Bexhill Road became loose in strong winds.
George O'Reilly, of East Sussex Fire and Rescue Service, said: "Conditions are too bad for us to work at heights to make it safe. We're waiting for the winds to drop slightly.
"The roof is flapping away in the wind and is in danger of coming off and landing in the road.
"It's already smashed some windows, so if it did go on the road it would cause significant damage to cars or pedestrians."
The Met Office has issued an yellow warning of wind - meaning "be aware" - for the Sussex coast for Wednesday.
Southeastern trains said it had been advised to run its trains at reduced speeds from 23:00 GMT on Tuesday because of the risk of landslips, flooding and falling trees during the strong winds and heavy rain.