TdF Stage 19 Preview: White Mountain...

"With our last act," says Tour director Christian Prudhomme, "with as many bends as there are climbs, we promise dazzlement, guaranteed by the almost permanent presence of the Mont Blanc."

Ethereal... At 4,808 metres Mont Blanc's peak is the highest in Western Europe. This photo was taken on February 4 this year, as seen from Chamonix. Source: AFP

No walk in the park... the road to Mont Blanc. Source: ASO

Recent years in the high mountains, Prudhomme has not only favoured stages of around 150 kilometres; somewhere in the final week, he also likes to plop in a sub-15km hors catégorie climb before a Cat. 1 summit finish. It seems to have a two-fold effect: tantalise GC contenders thinking about a long-range breakaway (and yes, Nairo, Romain, Richie and Daniel, we're looking at you!); and if that doesn't eventuate, racing on the final climb becomes more explosive (if the last mountain is too hard, the contenders fear blowing up if they go too early, and are more inclined to mark each other till the final kilometres, as happened on the stage to Finhaut-Emosson).

Short and dynamic... Source: ASO

Mountain passes & hills

Km 42.5 - Col de la Forclaz de Montmin (1,157m): 9.8 kilometre-long climb at 6.9% - category 1

Km 73.5 - Col de la Forclaz de Queige (870m): 5.6 kilometre-long climb at 7.8% - category 2

Km 96.5 - Montée de Bisanne (1,723m): 12.4 kilometre-long climb at 8.2% - category HC

Km 146.0 - Le Bettex (1,372 m): 9.8 kilometre-long climb at 8% - category 1

A tempter for those eyeing a long-range escape... Source: ASO

The Tour has never traversed the Montée de Bisanne (which runs parallel with the well-known Col de Saises) but rest assured: it's equal in difficulty to Wednesday's hors catégorie finish to the Emosson dam or the HC-rated Col de Joux Plane, the final climb of tomorrow. (Translation: the race will explode on its slopes.) Saint-Gervais Mont Blanc we've been to twice before at Le Tour, though not recently enough to draw a comparison. (The last winner was Rolf Jaermann of Switzerland, in 1992.) However it was included as the final climb at last year's Critérium du Dauphiné - and on the queen stage, no less.

Stage 7, 2015 Critérium du Dauphiné: Froome leaves van Garderen behind en route to Mont Blanc. Source: Tim de Waele/Getty Images

It was the second-to-last day and the stage previous, defending Tour champ Vincenzo Nibali had taken the lead from Tejay van Garderen. Still, the GC was far from assured with ten riders within a minute-and-a-half of each other, and so with 50km remaining Team Sky decided to make the race as hard as possible; by the time the groupe maillot jaune reached Sallanches, 20km from the finish at Le Bettex and the start of yesterday’s mountain time trial, Froome's hefty henchmen had whittled down the pack to around two dozen riders and boasted twice the numbers of the overnight race leader.

Lights out for Nibali. Source: Tim de Waele/Getty Images

In all-too-familiar scenes from this year’s Tour, the Skybots rode tempo till the final four kilometres before a devastating 2013 Ventoux-like attack from you-know-who could only be matched by van Garderen. Froome despatched the American in the last kilometre-and-a-half to win the stage but the latter reprised his race leadership, albeit by 18 seconds.

Stage 8, 2015 Dauphiné: Froome does it again, dropping van Garderen the next day to Modane Valfréjus to secure overall victory. Source: AFP

There was the same air of inevitability about the last stage of the 2015 race as there was before Froome took over the race lead on Stage 5 of this year's Dauphiné. What worked for Team Sky the day previous worked again on final climb to Modane Valfréjus, their leader's attack 2.5km out matched only, though again temporarily, by van Garderen, who would cede the jersey and the title to the Kenyan-born Brit. "Up until now I've just been looking to the end of the Dauphiné," said Froome, the race merely a training exercise for the main event. "Of course the Tour de France is the big objective, and I'm almost ready."

There was more to come from Froome in July 2015; this year he expects more still... Source: AFP

He was right, of course.

When he won the Dauphiné this year he said almost the same thing. "It's a boost of confidence ahead of the Tour de France but there's still some work to do before July. I'm not at my best yet. I've not raced much this year in order to be at my best during the third week of the Tour."

If his best is yet to come, we despair for his rivals. But if his best is now past him, as was the case in the previous two Tours he’s won, then today is arguably the best opportunity to unseat or at least ruffle his yellow feathers, or, come Sunday in Paris, earn a spot on the podium beside him.

If Porte wants to make the podium in Paris, he'll need to go earlier than he did on Wednesday to Finhaut-Emosson. Source: Tim de Waele/Getty Images

Christian Prudhomme, Tour de France race director, says...

"An amazing scenery: the Mont Blanc will be ever present all day. It'll also be the opportunity to discover two mountain passes of La Forclaz which will make a total of three with the Swiss Forclaz. We'll then follow the brand-new climb up the Mont Bisanne, which will hurt the legs of many before the final climb to Le Bettex through the tough paths up the Côte des Amerands."

Today's pièce de résistance... Source: ASO

What they say...

Chris Froome (Team Sky)

"There are two more big days to come now. Hopefully I didn't leave too much out on the road (in the time trial). At this point, two days out from Paris, we're just giving it everything we've got now. It's just these last couple of days to get the job done.

"(Today's stage) is a very tricky stage with a lot of tricky descents. There's talk about thunderstorms during the race. It's definitely going to have to be a stage where we stay right on our game. Of course, it's fantastic that I opened out my lead, but we can't relax and switch off now. We've got to see this through right to the end."

Richie Porte (BMC Racing)

"The goal is now the podium, so day by day I'm chipping away a little bit more time. We'll see how (Friday) goes and then the next day. It's a great honour to win the Bernard Hinault prize (for being the fastest up the Côte de Domancy in Thursday's time trial) and I think it shows that I'm climbing well. The next two days are full of hard climbs so I'm quite confident and we've got a great team, and I'm just looking forward to fighting for that podium.

"Let's just hope that I can chip away some more time. I really want the podium and I'm going to fight for it. I'm fit and healthy and I hope all of my bad luck is behind me now."

Daniel Martin (Etixx-Quick-Step)

"I never felt so good this late into a Tour de France; I also managed to avoid being sick and I'm happy for that. Two crucial mountain stages are now coming and I hope things will go the way I want."

Weather: The morning sky will be cloudy with rain showers. Strong rain expected with storms in the afternoon. 23°C at the start, 15°C at the top of the climb of the Montée de Bisanne. The wind will be very weak.