Manor Formula One driver Pascal Wehrlein was the unlucky one who found out what happens when you hit a puddle on slick tires. The weird dry-with-puddles conditions that contributed to Wehrlein’s spin out brought out a red flag for crews to help clear puddles from the track.

There were no good tire choices at the start of the Chinese Grand Prix. Free Practice 3 at the Shanghai International Circuit was soaking wet, but the circuit was mostly dry when qualifying came around. Key word: mostly. There were puddles on several parts of the track, particularly under the large bridges where water continued to drip on the track surface.

Those who played it safe and went out on the lightly grooved intermediate tires—specifically made for slightly wet and drying conditions—came back in with totally annihilated rubber. It was too dry for those tires on most of the circuit, causing them to degrade fast. Many teams opted to send out drivers on slicks, though, which contributed to Wehrlein’s oops.

Here we see Wehrlein open the drag reduction system flap in his rear wing to try and maximize straight-line speed on the pit straight. Unfortunately, that would contribute to his undoing.

Wehrlein’s car was on slicks, and when his car hit a bump in the middle of a puddle under one of the pit straight bridges, it lifted the car’s rear tires off the surface just enough to send Wehrlein’s car spinning into the inside barrier.

While the team that the bump was what caused the spin, Wehrlein’s slicks still contributed to the problem, as they don’t have any space to evacuate water and thus, hydroplane over it. They weren’t going to get Wehrlein any grip back after hitting that bump, as the low point under the bridge with the puddle was immediately afterward.

It didn’t help that DRS was open, either, as that switched the aerodynamic balance of his car further forward and off the rear wheels that could have used some extra grip at that moment. Essentially, Wehrlein had the perfect storm of things you don’t want when the rear of a Formula One car lifts a bit on a bump.

After this, the session was halted to clean up the puddles a bit more, and then everyone went back out on slick tires. Mercedes’ Lewis Hamilton, however, struggled with a power unit issue and couldn’t get a quick lap in.

Thus, the one car you’d least expect to see knocked out of the first qualifying session will start from last place, given that Hamilton already had a for a gearbox change heading into the Chinese Grand Prix. Hamilton’s gearbox had sustained damage in a collision with Valtteri Bottas in Bahrain.