Around into stage 19, Pinot, who had been placed fifth in the general classification, abandoned the race with a leg muscle injury. At the head of the race in the closing kilometres of the planned second to last climb, the hors catégorie Col de l'Iseran, Bernal attacked from the group of overall contenders, catching and passing final breakaway riders by the summit. Next over the top were breakers Simon Yates and Warren Barguil (Arkéa-Samsic), one minute behind Bernal, with the yellow jersey contenders following. Alaphilippe was dropped following Bernal's attack, and was two minutes behind at the summit. During the descent, the race was neutralised when a hailstorm caused ice and landslides to block the route to the final climb to Tignes, particularly a mudslide at the foot of the descent before Val-d'Isère. Times for the general classification were taken at the summit of the Iseran, with the stage victory and most combative rider of the day not awarded. As a result, Bernal, who had been in second place overall, moved ahead of Alaphilippe and took the yellow jersey. The stage was shortened from to .