Months before the skiers and riders arrived at Saturday’s skijoring competition, Tyler Smedsrud started planning the course’s challenges. But it only took a few days of warm weather to dash his original plans, forcing him to redesign the course at the last minute to battle the melting snow and mud pit at the Ouray County Fairgrounds.

The event features riders on horseback towing skiers and snowboarders through a course of gates and jumps, and organizers typically...