Debris-flow activity in Canyon of Lodore, Colorado: Implications for debris-fan formation and evolution

Large-scale characteristics of Lodore Canyon debris fans are dependent upon the bedrock and lithology of the mainstem and tributary canyons. Smaller-scale fan characteristics are dependent upon the magnitude and frequency of events from the respective drainage basin. Three distinct deposit ages were distinguished on individual fans and were tentatively correlated throughout the canyon.; During fall 1997 and late spring 1998, four debris flows aggraded fans in Lodore Canyon. Three of the four debris flows occurred in drainages that had been burned by forest fires. The debris flows were initiated during intense rainfall events.; Measurements from the Wild Mountain debris fan indicate that under current operating conditions of Flaming Gorge Dam, the Green River has a limited capacity to mobilize newly deposited debris-flow material. High release discharges equivalent to the 1997 high releases from Flaming Gorge Dam have a greater potential to rework newly deposited debris fans.