Colossal-Vail 50/50

The Colossal-Vail 50/50 returns to Vail, Arizona on December 5th, a trail running event that showcases the scenic beauty of the high desert section of the Arizona Trail east of Tucson. The course is designed by experienced members of the Tucson Trail Runners and spans various distances from ultra marathons to half-marathon lengths, catering to both new and seasoned runners. Participants can expect stunning views as they navigate through La Posta Quemada Ranch in Colossal Cave Mountain Park (CCMP) towards the scenic eastern boundary between the Sonoran and Chihuahuan Deserts.
On race morning at 7am, temperatures hover around a comfortable range of 30 to 45 degrees Fahrenheit with little wind. The UV index is low at 2.0, reducing concerns about sun exposure but still requiring adequate hydration due to dry desert conditions. Runners will face firm and slightly soft trail surfaces that provide both challenges and opportunities for quick footwork as they traverse the rugged terrain of La Posta Quemada Ranch and beyond.
This event has been running annually since its inception in 2015, drawing over a thousand participants each year who come to support local causes. The Colossal-Vail 50/50 also contributes significantly to scholarships for students at Vail High School through fundraising efforts by the Tucson Trail Runners and Fleet Feet Tucson, making it an essential part of the community's cultural calendar.
The course begins in La Posta Quemada Ranch within CCMP, offering runners a chance to explore scenic desert landscapes before heading south along the Arizona Trail. The terrain is varied with some climbs up to the northernmost ridges of the Santa Rita Mountains and descents back into open spaces near LPQ Ranch. Aid stations are well-placed at strategic points throughout each route, managed by experienced ultra runners who ensure proper hydration and nutrition.
Weather conditions in December typically involve cool mornings transitioning to mild afternoons with temperatures ranging from 30°F to 45°F. Humidity is low, averaging around 20%, which can make for a comfortable run but also requires careful attention to staying hydrated. Runners should be prepared for clear skies and minimal precipitation risk.