It was in the women's junior road race on Thursday, which was held on wet roads, that the 18-year-old crashed and suffered a serious head injury. She was taken to Zurich University Hospital by helicopter.
But her life could not be saved. She died on Friday.
What happened when Furrer crashed is not mapped out. According to Swiss media, the accident occurred in a forest area above the town of Küsnacht, on the eastern side of Lake Zurich.
Lived nearby
It took several minutes before Muriel Furrer was found.
"We currently have no reliable information," says Olivier Senn in the World Championship organization at a press conference, according to the AFP news agency.
Furrer, silver medalist in both the time trial and road race at this year's Swiss championships, lived in the town of Egg, just a ten-minute drive from the presumed accident site.
Her tragic passing has sparked sorrow and strong reactions in the international cycling community.
The Swiss Cycling Federation writes on its X-account:
"Our hearts are broken, we are lost for words. We have lost a warm-hearted and wonderful young woman who always wore a smile. We do not understand, we only feel pain and sorrow".
Flags at half-mast
Swiss authorities are investigating the death and the final World Championship races on Saturday and Sunday will be held as planned, although with scaled-down prize ceremonies. Additionally, a gala on Saturday evening has been cancelled. The flags at the World Championship area are flying at half-mast.
The hilly World Championship courses around Zurich are considered both difficult and dangerous, especially when it rains.
Cycling has been hit by several deaths during competitions in a short time. In Switzerland, Gino Mäder, 26, died after a crash at high speed in a downhill section. As recently as July, Norwegian André Drege, 25, crashed so badly in Austria, also at high speed, that he died.
Jonas Vingegaard and Remco Evenepoel are two elite cyclists who have been involved in violent crashes this year.
Many cyclists believe that the increasingly fast bicycles make the sport more dangerous.