India, May 23 -- In a freak-weather tragedy, a total of 21 runners were killed in the middle of a 100km marathon after a deadly cold snap struck the long-distance mountain race in northwest China's Gansu province on Saturday.

Freezing rain, battering hail, stormy weather and a sudden drop in temperature struck the ultra-marathon race, which kicked off near Yellow River Stone Forest, a popular tourist site in Jingtai County, Baiyin City in Gansu.

When the cold snap struck, the race, comprising 172 participants, was halted. Soon after, several runners were reported to have gone missing, and a rescue operation was launched.

By Sunday noon, the remains of the 21 victims had been recovered at the site of the tragedy, the rescue headquarters...