Lewis Hamilton says a bump that has appeared at Spa's Eau Rouge has "kind of ruined" the daunting corner, the Mercedes driver speculating that the issue may be linked to recent mudslides.
Hamilton clocked in third in Friday afternoon's second practice, narrowly behind pacesetter Max Verstappen and teammate Valtteri Bottas.
But during his day of running, the championship leader noted an uncomfortable change at Eau Rouge, in the compression zone of the corner.
"It's a great, great circuit," said the Mercedes driver. "It's very bumpy now through Eau Rouge, something's happening.
"They've kind of ruined it a little bit with whatever it is. I don't know if they have got a new patch [of asphalt] there, but there's a massive bump right at the compression point, which we've never had there before.
"It's really, really sharp up through the [body]. You feel it on the backside. But I'm sure they will fix it.
"I think has something to do with the mudslides, the rain, or something like that."
Hamilton's comments came just before a massive pile-up that occurred in the qualifying session of the W Series. Several drivers in succession slid off the slippery track at the bottom of the hill, right in the compression zone of Eau Rouge, and converged towards the same spot in the run-off area half-way up the corner.
The end result was a horrific pile-up from which everyone fortunately emerged shaken but relatively unscathed, although two drivers, Ayla Agren and Beitske Visser, were transferred to hospital to undergo further checks.
Spa-Francorchamps recently suffered massive floods following a spell of bad weather in the region, with several roads being damaged.
However, there were no reports of damage to the track itself.
There have been calls to change Spa's famous Raidillon following a series of high-profile crashes at the corner, the most recent of which was Jack Aitken's crask at the Spa 24 Hours, where the Williams reserve driver hit the barriers before bouncing back onto the track and into the path of oncoming cars where he was collected by another car.
While the corner itself may not require a change of layout, it has been suggested that moving the barriers on the left-hand side of the track further back would help diminish a bounce-back effect in teh event of an impact.
Spa is also planning to replace the tarmac run-of area at Raidillon with a gravel trap, a change that is also seen as a potential means of preventing cars from bouncing back into harm's way.
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