The Big South River Run in Colorado is a challenging Class IV-V section of water that runs for nine miles through the Roosevelt National Forest. This section contains a series of tight, technical rapids, including S-turn, Triple Drop, and Super Collider. The best time to float this section is in late spring to early summer when the snowmelt is at its peak, with recommended CFS levels of 400-700. Due to the technical nature of the rapids, this section is recommended only for experienced paddlers, and a guide is strongly advised.