The crash that forewarned F1 on its darkest weekend

As of the 2024 Chinese Grand Prix, there have been 1,106 official world championship grands prix in Formula 1.

Of those, perhaps there is none as seared into the collective memory of F1 as race #551 - the 1994 San Marino Grand Prix weekend.

Roland Ratzenberger was killed on April 30th, 1994 in a qualifying crash, before one of the world's biggest sporting icons, three-time world champion Ayrton Senna was killed whilst leading the race on May Day, 1994.

They were the first fatalities during a grand prix weekend since Riccardo Paletti was killed in a start-line accident at the 1982 Canadian Grand Prix.

But that Imola weekend was already under something of a cloud, following a vicious accident for Senna's protege, Rubens Barrichello on the Friday - April 29th, 1994.

Barrichello's accident at Imola

Remarkably, despite driving for Jordan, Barrichello was the lead Brazilian driver in the championship heading into Imola following a fourth and first career podium in Brazil and at Aida in Japan, respectively.

His mentor Senna, having finally gotten his hands on a Williams, had 0 zero points after spinning off at home in Sao Paulo and getting nudged off by Mika Hakkinen at the start in Aida.

Back in 1994, F1's qualifying system was a session apiece on Friday and Saturday, with Senna ultimately claiming his 65th, and final pole position with a 1:21.548 lap.

But on the Friday, F1 was shocked to its core when Barrichello hit a kerb at the Variante Bassa chicane and was catapulted into the tyre barrier at 140mph, in an accident that recorded 95g.

After the vicious impact, the unconscious Barrichello's car came to rest on its side as the marshals casually flipped the shattered Jordan back right side-up. That would be unthinkable today.

Upon regaining consciousness in the medical centre, Barrichello was greeted by a watchful Senna, his life having been saved by Professor Sid Watkins after his tongue blocked his airway.

Over than light injuries, including a busted lip and a broken nose, he was able to leave hospital and would watch the rest of the weekend's events on TV.

What happened next?

After Barrichello's accident, a feeling of 'that was a lucky escape' grew as Friday gave way to Saturday - but F1's luck was about to run out.

Ratzenberger's front-wing failed on a qualifying lap approaching the Villeneuve kink - the fastest part of the circuit at nearly 200mph, after a kerb strike on his previous lap.

The wing became lodged under his front wheels, making the front brakes useless as he hit an exposed concrete wall. The impact was 500g - the highest ever-recorded in F1.

Ratzenberger suffered a basilar skull fracture and was killed instantly on impact.

Senna was greatly impacted, and eventually chose to race, with the plan to unfurl the Austrian flag if he won the race in honour of the fallen Simtek driver.

That flag was found in the wreckage of the FW16 at Tamburello, nearly 24 hours after Ratzenberger's death.