There are essentially 7 danger spots on the Upper G at release level and in/around the "normal" commercial raft lines. These spots include 1)Initiation, 2)Sperm whale rock in Iron Curtain, 3) the entire left side of Lost Paddle from third drop to forth, 4)Right side of fifth drop of Lost Paddle, Tumblehome, 5) Center/bottom of Conestoga, 6) Shipwreck Rock and 7) Fingernail rock. There are NUMEROUS other undercuts and nasty hydraulics in and around the smaller channels. For the most part the hazards along the main channels are fairly easy to avoid, if you follow someone down who knows the river and can point them out prior to each rapid. Most private boaters are very helpful on the Upper G. It is a very fun river. The lines are wide, the waves are big and the scene at Sweets Falls is one of my favorite places to stop to "people" watch. Have fun. Hope this helps a little. Dan