A CCTV camera captured the moment a block of ice plummeted from the sky, narrowly missing a street cleaner.
Council worker Serhiy Myeshkov said he felt lucky to be alive after the sheet of ice smashed on the road metres away from him.
It is thought to have fallen from a plane flying overheard.
Mr Myeshkov was working in Kew, west London, under the busy Heathrow flight path when the ice crashed down nearby.
He told the Richmond and Twickenham Times: “I was sweeping on the other side of the road, then heard a loud boom.
“A piece of ice, maybe 10kg big, fell from either a plane or from the sky. It all happened very quickly.
“I wasn’t scared, but it could kill you. I feel lucky.”
The falling ice was captured on a taxi firm’s security camera at 9am on Wednesday.
Employee Amir Khan, 39, told the Evening Standard: “It was like the start of a disaster movie, like The Day After Tomorrow.
“It made such a loud noise like a meteorite crashing down. The street cleaner was so confused and scared. Everyone came running out to look at the sky. It was crazy.”
A spokesman for the CAA said: “Although ice does very occasionally fall from aircraft, it can also be the result of meteorological phenomena.
“We receive around 30 reported ice falls every year, although we are not certain how many of these incidents are the result of ice falling from an aircraft.”