This was a stage for the ages, but its images are already seared into memories. The peloton, splattered and scattered by the rain and cobbles along the road to Arenberg Porte du Hainaut. The Dutch rider Lars Boom, his face camouflaged by mud, raising his hands in grim triumph. Vincenzo Nibali, surprising us all with his nimbleness and daring, taking swingeing chunks out of his main general classification rivals.

And then the crashes, of which there were far too many to keep count – although the official Tour de France medical bulletin listed 12 riders who needed treatment. Among them was Jurgen van den Broeck, a top 10 contender, who flipped over his handlebars as he was dunked into a ditch.

Afterwards Garmin-Sharp team manager Jonathan Vaughters described it as “absolute war”. And there was one major casualty: Britain’s Chris Froome, the 2013 champion, who trudged despairingly into the Team Sky car with just over 70km of stage five remaining.

Froome had started the day with his left knee bandaged and his left wrist supported by a lightweight splint, the painful legacy of a crash on Tuesday. But two further spills weakened his body and crushed his spirit.

Later he reached for a familiar adjective – “devastated”. But his team-mate Geraint Thomas, who rode so boldly to steer his new team leader Richie Porte into seventh, admitted he had feared the worst when Froome went down after 33km.

“When Froomey crashed early on, it was like: not again‚” he said. “He was just behind me and I thought: that sounds nasty. But he is always positive and he was saying: ‘I will keep going and be fine on the cobbles,’ but then he went down again and it was too much to take.

“He must have been in bits, but mentally it will be harder on him than physically. No cyclist is indestructible and three within 24 hours is hard to take.”

On a stage with the cobbles of Paris-Roubaix – the most famous of the spring classics – at its fulcrum, the weather seemed to have reset itself to mid-April. The rain, which began not long after dawn, rarely stopped its monotonous beat. Soon tarmac was flooded and cobbles were as skiddy and tricky as black ice.

It was a day for stoic faces and grim resolve, for waterproofed jackets and long tights, but there was no escaping the cold and wet. Often the riders aquaplaned past the sparse crowds in a haze.

Due to the bad weather, two of the nine cobbled sectors were removed before the start – the 1,000m at Mons-en-P V Le, ranked the highest five-star difficulty in the Paris-Roubaix, and the 1,400m stretch from Orchies to Beuvry-la-Forêt. That meant there were 13 kilometres of cobbles, not 15.4km. It mattered little. Long before the first cobbles there were crashes.

Sébestien Minard skidded near a roundabout and lost his bike. Marcel Kittel did the same round a corner, breaking his cleats. They were just two from many.

Later the peloton split as it swept around a giant roundabout and there were crashes on both sides of the road, including two GC contenders Alessandro Valverde and Teejay van Garderen. But it was Froome who had suffered most and, after speaking to medics, decided he could not continue.

The Spanish rider Joaquim Rodríguez reckons riding on the cobbles is like giving Rafael Nadal a ping-pong bat not a tennis racket. Van den Broeck and Andrew Talansky, who were among the unseated, might agree. But it made for thrilling racing.

Halfway through the cobbles Alberto Contador, who ended up losing 2min 35secs on the stage, was dropped by Nibali. But there was carnage everywhere.

With 15km remaining there were just over a dozen men out in front including Nibali, Peter Sagan and Fabian Cancellara. At that point Sagan and Cancellara were favourites for the stage but on the last stretch of cobbles, Boom escaped to record a famous victory. Nibali retains the yellow jersey by two seconds from his Astana team-mate Jakob Fuglsang, and was the biggest winner of the day.

Meanwhile Thomas and Porte were also happy after escaping Contador and putting Team Sky in a position to challenge in the mountains. “I saw Contador was struggling so I said: Richie, get on my wheel and we will just smash it and see what happens,” said Thomas. “I actually enjoyed it then. Once it all broke up and you could take your own line it was awesome.”

Afterwards, as the world’s media crowded around the Team Sky bus demanding an instant reaction to Froome’s withdrawal, Sir Dave Brailsford chose to speak as a bike fan as well as a team principal.

“It was exciting, wasn’t it?” he said, face lit up with enthusiasm. “You’ve got to say that. It might not have worked out for us but the way Nibali rode was just unbelievable. To ride away from Cancellara and Sagan on the cobbles, we will remember that for a long time.”

Froome, meanwhile, has returned to his home in Monaco for urgent repairs. Speaking earlier this year, he said stage five “is not a stage where you can win the Tour, but it’s definitely one where you can lose it”. The fact he was proved so spectacularly right will give him no comfort.