The F1 circus is coming to the end of its year-long journey as the paddock descends on Sao Paulo, Brazil for the Grand Prix at Interlagos. Fortunately for us fans there is no better place for a championship decider, as this track has taught one simple lesson time and time again – expect the unexpected!

One of the unique features of the Interlagos circuit is that the general layout has escaped any major change since returning to F1 full-time in 1990. The track surface however is a completely different story – it’s extremely bumpy, and while the track has been resurfaced numerous times to try to reduce the bone-crushing ride, it’s still one of the most bumpy and unforgiving pieces of track the cars will drive on all year. Add to that the short length to the lap and the constant elevation and corner gradient changes, the venue demands the most of both car and driver. Sauber even withdrew both cars in 2000 for safety reasons after several rear wings shook themselves to pieces on the start/finish straight.

With the circuit running anti-clockwise the driver’s neck takes such punishment that the cars have been known to run with extra padding for the drivers head to lean on. At turns 6 and 7 they will be pulling over 4G for nearly 5 seconds, and on race day they’ll be doing that 71 times.

The biggest issue facing the drivers and teams though is, believe it or not, the altitude. Interlagos is a massive 800 metres above sea level (about 2,600ft for fans of imperial measurements). This means the air is thinner and this has a noticeable impact on driver fitness and engine performance. The altitude is such a big problem that the engine manufacturers estimate that the teams will lose around 8% in power, which is around the same engine power as a small family car. Because of this, the use of KERS is crucial around the lap, and if it’s not available for whatever reason the effect will be much more noticeable than at any other Grand Prix.

History has also shown how random the results can be here. We all surely remember what should have been a fairly straightforward championship win for Hamilton in 2008 turn into a last lap, last corner mad dash to take it by a single point from Felipe Massa.

Giancarlo Fisichella achieved an unexpected maiden win here in a not-so-competitive Jordan back in 2003, while in more recent times Jenson Button and Sebastian Vettel had a calamitous qualifying session in 2009 to line up 14th and 16th. Even the most unlikely of things can play a crucial role – such as an advertising board falling on Jean Alesi’s Prost in 2000.

Then there’s the elephant in the room – the weather. A lot of the key points in the history of this track have revolved around the completely unpredictable weather patterns for qualifying and the race. And the current long-term forecast for this Saturday and Sunday? Rain. Lots of rain.

All of a sudden, a 13 point gap between Vettel and Alonso doesn’t seem so big, does it? I think we’re in for a cracking season finale.