Rain, and Spain. Those seem to be Chris Froome's major worries in the next few days after Alberto Contador, Joaquim Rodríguez and Alejandro Valverde all rode strongly in the tough hilly time trial here, and with thunderstorms forecast, the race leader seems increasingly concerned about the tricky descent from l'Alpe d'Huez off the Col de Sarenne on Thursday. He called for the organisers to cut the descent and the second climb of the Alpe if the weather does not co-operate.

“It’s a dangerous descent, if it’s raining it will be even more dangerous,” said Froome. “It would be sad not to do Alpe d’Huez twice as it is something special, but safety comes first. If it rains I hope the organisers will take the decision to have the finish on top the first time.” Following the race leader’s criticism of Contador for attacking on a descent, it will not endear Froome to those who believe that downhill skills are as much a part of a bike racer’s repertoire as uphill power output.

Froome had expected to limit his losses here by racing conservatively on a course that rewarded risk takers, so his third stage in the race seemed to come in spite of himself. It means he is only the second Briton along with Mark Cavendish to take three stages in a single Tour, and there could be more to come. There will be further opportunities for him, and he currently leads the King of the Mountains standings, meaning that if the next few days go to plan his haul in Paris could be a rich one.

The winning margin was narrow, just nine and 10 seconds respectively ahead of Contador and Rodríguez, with Roman Kreuziger and Valverde also within 30sec, but he has still strengthened his position thanks to a poor ride by the man who started the stage as runner-up, Bauke Mollema of Holland, who slipped to fourth overall. That leaves Contador and Kreuziger within five minutes, Mollema and Nairo Quintana between six and seven. Barring the unforeseen, it should see the Kenyan-born Briton to Paris.

Power output has exercised many observers of Froome’s performances, but this win came down to aerodynamics and management. In split-screen pictures on the same stretch of the second tough climb in the course, Froome and Contador were chalk and cheese: the Briton tucked on his tribars, the Spaniard climbing out of the saddle. Hardly surprising then that Froome more than overturned a 20sec deficit on Contador up the climb.

He then lost 10sec as he switched to his usual time-trial bike for the final descent, which was more straightforward than the first, which resembled a go-karting course with its rapid-succession of blind-exit bends, and lumps and bumps, with the added twist of a capricious thunderstorm briefly soaking the roads, leaving wet patches for later starters. Contador had gone faster on the more technical descent, but remained on a less aerodynamic machine for the second, and that decision may well have cost him the stage victory.

Midway through the toughest final week in the Tour in recent years, the Spanish and their team-mates are advancing en masse deep into the top 10; France’s cyclists have only three days to win a stage and avoid their worst Tour ever on the other hand. On Wednesday they lost their only man in the top 20 when Jean-Christophe Péraud, ninth overall in the morning, crashed twice, the first time while warming up, when he suffered a hairline collarbone fracture.

He still raced in the afternoon, a feat of courage which was given the same reverence and minute-by-minute coverage on French television as the arrival of a Royal baby, but took risks on the descents that would have terrified most human beings without a broken bone in their bodies; his second crash of the day on the final bend was a heavy one, he landed on his injured right shoulder, and was out of the race for good.

On Thursday, the twin climbs of l’Alpe d’Huez await, assuming the weather co-operates and the organisers stick to their guns. Watching Péraud splatter into the tarmac, and all the other riders in the race flirting with the adhesion limits of their tyres on the descents at high speed – one at least was clocked at over 97kph – was to be reminded that safety in the Tour has always been a relative concept at best. Barring Acts of God, it will be an epic set piece, and God willing, one without accident.