The Sluice Box to Green Riffle river run on the Klamath River in California is an exciting and challenging stretch of water that offers stunning scenery and thrilling rapids. The river run difficulty is rated as class III to IV, and it features several obstacles such as rocks, drops, and powerful currents that require excellent boating skills to navigate safely. The best time to float this section of water is during the late spring and early summer months when the water levels are high, with a recommended CFS of 1500 to 3000. Experienced boaters will find this run to be exhilarating, while novices are advised to seek professional guidance before attempting it.