The last time Stuart O'Grady experienced such atrocious weather on a bike, he had to dive under a tractor to hide from hailstones the size of golf balls.

That wasn't the case at the snow-hit Tour of Flanders on Sunday, but still the reigning Paris-Roubaix champion and his CSC team suffered arguably their worst ever day of racing.

CSC harbored realistic hopes of seeing Milan-SanRemo champion Fabian Cancellara grab his second classics scalp of the season.

In the end the Swiss was among the pre-race favourites duped by Belgian champion Stijn Devolder, who secured his first Flanders win after a long breakaway 26km from home.

O'Grady failed to finish the 264km epic, raced over tight, cobblestoned roads from Bruges to here, with 17 climbs thrown in for good measure. But neither did more than half the peloton.

After being besieged by hail, cold and snow, the Australian was just happy to avoid disaster as he battles for form following a long absence from the peloton due to a career-threatening crash at last year's Tour de France.

"It was an extreme race, really nervous with the weather and personally, my body just doesn't function too well in that kind of cold," O'Grady told AFP.

"In races like this you need things to fall in your favour, and it doesn't happen every race. Over half the team crashed, we had quite a few punctures and I had one particularly shocking moment.

"I think we're all a bit disappointed after coming in with such big expectations, the whole team was firing on all cylinders."

After a sunny start in Bruges, the typically changeable Belgian weather kicked in ferociously after the first 100km.

"It just came out of nowhere. Next minute the whole road was white with hailstones and it probably went from 10 degrees to zero in a couple of kilometers," added O'Grady.

As the race to get to the front ahead of crucial climbs kicked in, riders began coming down on the slippery roads and cobblestones.

One unfortunate Spaniard — Angel Gomez Gomez — flew over the handlebars when he rode straight into a curb, and broken gears ended the victory hopes of Belgian Leif Hoste, a three-time runner-up.

A spate of incidents meant CSC were always playing catch-up, and in the end a late rally by Cancellara proved futile.

"Stuart punctured early in the race and he spent a lot of energy trying to get back into the race," said the team's assistant manager Scott Sunderland.

"Matti Breschel then crashed on the Steenbeekdries (climb), Allan Johansen punctured out of the front group just after Taaienberg (climb), Karsten Kroon punctured on top of the Muur and Marcus Ljungqvist crashed on the descent to the Paterberg (climb).

"I lost guys too early, and too regularly."

Sunderland felt particular sympathy for O'Grady, who — given his tame demeanor at the end — might be one of the riders in need of fattening up for the chilly northern classics.

"We had everything today — sun, rain, hail, snow. And we went down to four degrees at the bottom of the Kwaremont (climb)," added Australian Sunderland.

"Stuart had good legs until there, but that was the breaking point. The cold just killed him.

"He tried to keep pushing, hoping he would warm up but it didn't happen. We've got a few guys who really suffered, especially the three with under five percent body fat."

CSC, as reigning champions of Paris-Roubaix, will now turn their attention to next Sunday's 'Hell of the North.'

"We'll be one of the teams to beat. But there's a lot of good riders and a lot of good teams out there," added O'Grady, who admits he is at 85 percent of full fitness.

"To win these big classics it takes a lot more than a lot of good luck."