A participant in the demanding 250-mile ultramarathon across northern Arizona tragically passed away on Tuesday following a medical incident, according to statements from race organizers and local authorities.

First responders arrived at the scene to assist a woman in her 40s who had been competing in the event and collapsed at a trailhead located in the Groom Creek area, south of Prescott. This was confirmed by Paul Wick, a spokesperson for the Yavapai County Sheriff’s Office, on Wednesday.

Erika Snyder, co-director of the Cocodona 250 ultramarathon, acknowledged the fatality but refrained from disclosing additional information at the family’s request. She expressed the community’s gratitude and asked for thoughts and prayers for the runner’s family, friends, fellow competitors, volunteers, and first responders. The event organizers shared on social media that the race would proceed in memory of the runner, encouraging all participants and support crews to honor her on the trail.

While ultramarathons push the limits of human endurance, fatalities are uncommon when considering the large number of participants in a sport that has seen a surge in interest globally, with events held in locations ranging from Death Valley to the Himalayas. For example, a woman from Michigan tragically died last year during a 100-mile race in the mountains of southwest Colorado.

The Cocodona ultramarathon is recognized as one of the most challenging in the United States, featuring a course that ascends over a mile in elevation twice and traverses through Sedona, starting from Black Canyon City. Competitors have 125 hours to complete the course, which connects some of Arizona’s most renowned trails, as reported by CBS affiliate KPHO.

This year’s event commenced early Monday morning, and the overall winner, Rachel Entrekin, completed the race on Wednesday afternoon to enthusiastic cheers in Flagstaff, also setting a new course record.

Due to the race’s increasing popularity, organizers plan to implement a lottery registration system for next year. Aid stations along the route allow participants to refuel, hydrate, and make equipment adjustments, with medical teams positioned throughout the course. In this multi-day event, runners often rest on the ground during the race.

In 2021, adverse weather conditions including freezing rain and strong winds were linked to the deaths of 21 runners during an ultramarathon in northwestern China.