The 26-year-old Mäder crashed after a left-hand turn on a fast downhill road approaching the end of the mountainous fifth stage into La Punt. His fall of about 30 meters was stopped by a stream.
“Gino lost his battle to recover from the severe injuries he sustained,” his Bahrain-Victorious team said in a statement. “Despite the best efforts of the phenomenal staff at Chur hospital, Gino couldn’t make it through this, his final and biggest challenge, and at 11:30 a.m. we said goodbye to one of the shining lights of our team."
Medical staff who reached Mäder found him motionless in the water, race organizers said Thursday. CPR was performed on him before he was airlifted to the hospital.
“Our entire team is devastated by this tragic accident, and our thoughts and prayers are with Gino’s family and loved ones during this incredibly difficult time,” Bahrain-Victorious said.
Police in the Swiss canton of Graubünden said a joint investigation with prosecutors wanted to hear from witnesses who might have seen and filmed the incident.
The Tour de Suisse is a preparation race for next month's Tour de France.
Mäder's death was announced about 30 minutes before the scheduled start of the sixth stage in the eight-day race. The start was delayed and riders gathered in a silent tribute before the stage was canceled.
The peloton rode together in tribute to Mäder for the final 30 kilometers (18 miles) of Friday's scheduled route. The race should resume Saturday.
“Devastated by the news," said world champion Remco Evenepoel, who is in fourth place in the race standings. "My heart and strength is with Gino’s family, friends, teammates.”
Evenepoel earlier criticized Thursday's stage after finishing the day in 10th place.
“While a summit finish would have been perfectly possible, it wasn’t a good decision to let us finish down this dangerous descent,” Evenepoel wrote on his Twitter account. “As riders, we should also think about the risks we take going down a mountain.”
A second rider also crashed at the same spot. Magnus Sheffield of the United States sustained a concussion and bruises and was treated at a local hospital.
In previous incidents, Belgian rider Wouter Weylandt was killed in a crash on a descent at the Giro d'Italia in May 2011. Another Belgian rider, Antoine Demoitié, died after crashing at the one-day Gent-Wevelgem race in March 2016.
Mäder was one of Switzerland's best young riders. He won a stage at the 2021 Giro and placed fifth overall in the Spanish Vuelta that year. He also was fifth in the Paris-Nice stage race in March.
“We are heartbroken," Tour de Suisse organizers said in a statement. "Gino, you’ve been an excellent rider but even more a wonderful person. Always smiling and making people happy around you.”
Mäder was asked on Sunday by a reporter at the race finish what would make him happy at the end of the week-long race. “If I’m still healthy and I enjoy my home race, maybe have some success with the team,” Mäder had said.
Team manager Milan Erzen praised the rider, saying his “talent, dedication, and enthusiasm were an inspiration to us all.”
“Not only was he an extremely talented cyclist,” Erzen said, "but a great person off the bike.”