A participant in a grueling 250-mile ultramarathon on trails across northern Arizona died Tuesday after experiencing a medical emergency, race organizers and local law enforcement said.

First responders attended to a woman in her 40s who was participating in the race and collapsed at a trailhead in the Groom Creek community south of Prescott, Yavapai County Sheriff’s Office spokesperson Paul Wick said on Wednesday.

Cocodona 250 ultramarathon codirector Erika Snyder confirmed the death and declined to provide further details at the request of the runner’s relatives.

Cocodona 250 ultramarathon codirector Erika Snyder confirmed the death.…