In an instant, and just as it was becoming even more thrilling, the most exciting Tour de France in decades became truly bizarre.
A violent hailstorm threw cycling's greatest race into chaos Friday, forcing organizers to cut short a nail-biting stage in the high Alps because riders were speeding headlong toward a road that, unbeknownst to them, had suddenly become covered with ice and giant puddles and cut in half by a rock slide.
Concerned for riders' safety on mountain roads that can be dangerous at the best of times, race organizers made an on-the-spot and extremely rare decision that the stage couldn't continue.
"When you look at the images, the decision to stop the race was self-explanatory, considering how quickly it happened," Charly Wegelius, director of the U.S.-based EF-Education First team, told ESPN's Bonnie D. Ford. "It's not as if they had three hours to make a decision. They literally had minutes.''
The shock wave was immediate and heavy in repercussions. With the riders unable to reach the planned finish at the ski station of Tignes, organizers decided their placings would instead be based on their time at the top of the highest mountain pass of this Tour -- the Iseran, at 9,090 feet above sea level -- which leading riders, but not all, had just scaled when the race was stopped.
Just like that, Colombian rider Egan Bernal found himself in the yellow jersey.
He sped away from Julian Alaphilippe on the climb and reached the top 2 minutes, 10 seconds ahead of the Frenchman, who had held the race lead for a total of 14 days.
Bernal was speeding down hairpins on the other side, with Alaphilippe hot on his trail, hoping to save his race lead, when they received the order to stop racing.
"I don't really know what happened. I was speeding, attacking, and everything was going well and then they told me to stop. I didn't want to stop," Bernal said through an interpreter on French television. "When they told me that I was the race leader and I had the yellow jersey, I couldn't believe it and I still can't believe it."
Organizers scrambled to deal with the disarray and riders clambered off their bikes, not immediately sure what was going on. Exceptionally, there was no winner of Stage 19, because no one had reached the finish.
"This Tour is crazy," race director Christian Prudhomme said. "We would never have imagined a day like this."
Having made France dream of having a first Tour winner since 1985 and having contributed more than anyone to make this Tour memorable with his punchy riding, Alaphilippe lost the race lead as the Champs-Elysees in Paris was almost within touching distance.
Prudhomme said the hair-raising speeds of Bernal, Alaphilippe and other riders on the downhill from the Iseran in part prompted the decision to stop the race.
"We could see that they were taking risks, and we knew that they couldn't go much further," Prudhomme said. "The only thing that counts is the riders' health and safety. It was impossible."
Bernal, who races on the Ineos team, was 1:30 behind Alaphilippe at the start of the stage. Ahead of Saturday's final trek in the Alps, the last competitive stage before a traditional processional ride to Paris, the 22-year-old Bernal is now in an ideal position to become the first Colombian to win cycling's biggest race.
Defending Tour champion Geraint Thomas, who entered Friday in third overall, said his job now will be to help teammate Bernal come home with the victory.
"He's been incredible from the start. He's a phenomenal talent," Thomas said. "We all said last year he'll win the Tour one day. Maybe we didn't expect it to be this year, but he's been super strong and he's shown, climbing, he's one of the best here. So we just need to finish this job now."
Prudhomme said riders' timings at the top of the Iseran were taken the old-fashioned way, with a watch. Normally, organizers furnish riders' placings almost immediately after each stage. On Friday, organizers first provided delayed provisional standings and then tweaked the results in official standings that took about three hours to finalize.
Bernal now leads Alaphilippe by 48 seconds. Thomas is third, 1:16 behind Bernal -- not 1:03 back as organizers had first announced.
Alaphilippe said he had been bracing to lose the lead on the tough Alpine stage, but no one had imagined it would happen in such dramatic circumstances.
"I gave it all. I don't have any regret," he said. "I've been beaten by [something] stronger than me."
The sudden storm turned summer into almost winter in just minutes, with a dusting of white covering what had been lush summer pastures of green. A snowplow driver tried to clear away the slush, throwing up waves of water, on the road flooded with torrents of water and ice.
It wasn't the first time that Alpine weather had thrown Tour organizers' plans into disarray. At the 1996 Tour, what had been planned as a 118-mile stage from Val d'Isere to Sestrieres was slashed to 28.5 miles because of snow, with both the Iseran and Galibier passes not climbed as planned.
Black storm clouds could be seen looming on the horizon as Bernal went over the top of the climb.
Although Bernal was all smiles as he stepped into an Ineos car, other contenders, including Alaphilippe, looked disappointed. The French rider waved his left arm in disdain and swerved back and forth across the road. Colombian rider Rigoberto Uran looked angry.
But Marc Madiot, the manager of the Groupama-FDJ team, applauded the stoppage.
"Safety is the first priority and the decision to stop the stage seemed to be the only decision to make," he said. "Imagine that the race had a continued and a rider had plunged into a ravine."
The Associated Press contributed to this report.