A 100km (60-mile) ultramarathon in the Yellow River Stone Forest, a tourist site in Jingtai county, Baiyin, northwest China's Gansu Province was suspended after freezing rain and high winds hit the high-altitude track on Saturday (22 May).

The race began at 9:00 local time (01:00 GMT) on Saturday, with several of the participants setting off wearing just shorts and T-shirts.

However, at about 1pm, a mountainous section at a height of about 2,000 metres (6,500 feet) about sea level of the race was hit by sudden hail storm, freezing rain and gale winds, which caused temperatures to plummet, according to China Central Television (CCTV) reports.

Many runners reportedly lost their way on the route as the weather affected visibility with several runners suffered from hypothermia. Some even passed out due to the cold.

A participant said that there was no forecast of the sudden extreme weather.

More than 700 rescuers were deployed, assisted by thermal-imaging drones and radar detectors, according to the Xinhua News Agency.

By Sunday morning, 151 of the 172 race participants had been confirmed safe, with eight in hospital. Another 21 were found dead, according to the officials.

Among the casualty were Liang Jing and Huang Guanjun, two of the country’s top long-distance runners.

Liang Jing won China’s Ultra Gobi in 2018 and came second in the Hong Kong 100 ultra trail race in 2019. Guanjun won the men's hearing-impaired marathon at the 2019 National Paralympic Games.

The deaths have sparked public outrage on Chinese social media, over the lack of contingency planning by the organiser.

The local government has formed a team for an in-depth investigation on the cause of the incident, the People's Daily reported.

The mountain trail race is an annual event organised by authorities in Jingtai county and Baiyin. This year, it's the fourth edition.

Photo Credit: Xinhua