Haas driver Grosjean clipped Daniil Kvyat’s front wing on the opening lap, before plunging into the barrier at high speed.
The impact cut Grosjean’s car in half, with the wreckage engulfed in flames.
Grosjean survives big crash on Lap 1, Bahrain Grand Prix red flagged
Remarkably, the Frenchman was able to walk away from the shocking scene with minor burns on his hands and ankles.
F1’s ever-improving safety measures were praised in the aftermath of the accident and Hill marvelled at the 34-year-old’s escape.
“This was particularly graphic, particularly shocking,” Hill told Sky Sports.
“Nobody in their right mind could understand what Romain has been through. It’s a miracle that he is alive.”
He added: “Normally I’ve got some experience to draw on to be able to contribute something, but I’m absolutely flabbergasted. I’ve seen the images of him getting out and the speed he went into the barrier is absolutely terrifying.
“He’s penetrated three levels of the Armco barrier. It’s unbelievable that he clambered out.”
Former driver and current Sky Sports commentator Martin Brundle echoed his fellow Briton’s sentiments.
“That’s a miracle,” Brundle said. “It pierced the barriers like a can opener.
“They’re constantly trying to improve the structural stability of the chassis and that’s just saved his life. That is extraordinary. Romain went with the front half of his chassis.”
Ex-Renault driver Jolyon Palmer credited the halo crash-protection system around Grosjean’s cockpit with saving his life.
“I have never seen [anything like it] before – how the front of the car punctures straight through the Armco [barrier], the rear falls away completely, the car is split in two and Grosjean is left in the Armco,” Palmer told BBC Radio 5 Live.
