Michael Schumacher, the most successful driver in Formula 1 history and one of the world's highest-profile athletes, remains in critical condition after suffering severe head trauma in a skiing accident in the French Alps, hospital officials said Monday.

Doctors who have been treating Schumacher at the University Hospital Center of Grenoble said at a news conference that it was too early to say what the driver's prognosis might be.

In a prepared statement, Schumacher's family thanked doctors for doing "everything possible to help Michael." They also thanked people around the world for the outpouring of support.

The German, who retired from the elite motorsport for the second time in 2012, fell and hit his head on a rock Sunday, said the director of the Meribel resort where Schumacher was skiing.

Schumacher was in a coma when he arrived at the hospital and required immediate brain surgery, officials said. So far, he has undergone one operation and is being kept in a coma, they said Monday.Schumacher, who turns 45 Friday, won a record seven world titles in his spectacular Formula 1 career and "also holds nearly every scoring record in the book by a considerable margin," according to the motorsport's official website.

He dominated the competition for the best part of a decade, winning five world championships in a row between 2000 and 2004.

Schumacher suffered serious injury once during his career in the high-speed sport, breaking his leg in a crash at the British Grand Prix in 1999.

British journalist Kevin Garside told CNN that Schumacher is "a very good skier" but acknowledged that he is "fearless" -- like most Formula 1 drivers.

"These people don't recognize fear like you and I do. There is no gene in their body that lets them go slow," Garside said.

"Schumacher wasn't a skier when he joined Ferrari (in 1996), but by the end he was excellent," he said. "Each year Ferrari used to have a media week in the Alps in Italy and they would always have a race -- and it was always Schumacher who won. He was a genuinely quick skier.

"But he was always very mindful of the danger around him," Garside added. "I approached him for an interview at the top of the slope, and he said it would have to be quick as he wanted to check the piste. That meant he wanted to make sure he understood the slopes, the cambers, even though it was only a fun race."