Lessons Learned from the Tragedy during the 100 km Ultramarathon Race in Baiyin, Gansu Province on 22 May 2021

Twenty-one runners died of hypothermia during the 100 km Ultramarathon Mountain race in Baiyin, Gansu Province on 22 May 2021. The was caused by a combination low temperatures, precipitation, and high winds associated with typical large-scale cold front passing site that morning. Based historical hourly records 13 meteorological surface stations over past six years, temperature (3.0°C) apparent (−5.1°C) at 1200 LST as well gust wind speed (11.2 m s−1) 1100 day tragedy were found to be within top or bottom 5th percentile for month May. precipitation only moderate this time, but when lower than 3.0°C, greater 11.2 s−1, 0.1 mm any adjacent three hours combined together, fell 0.1% cases. European Centre Medium-range Weather Forecasting model produced reasonably good forecasts one seven days before event, respectfully. study, lessons can learned from are summarized an academic perspective: Hazard impact high-impact weather events should developed increase value forecasts. Probability issued government agencies communicated public. And more importantly, knowledge how evaluate delivered public future. We would like extend our deepest condolences families loved ones people who lost their lives tragedy, including 21 officer. efforts honor those highlighting forecasting calling action