We mostly ran class II and class III rapids, but we hit two class IVs on the first full day in the raft. One of these class IVs, the Wild Sheep Rapids, gave us a run for our money. I was in the paddle boat, the heart of the action, with our guide Kale and five other's from our crew. We hung back and waited for the dory boat to chart its course through the giant crashing waves. The big fiberglass dory would always go through first and the rafts would follow; if that thing got loose you definitely didn't want it at the back of the line clobbering everyone in front of it. When we saw the dory slip through unscathed, we took off into our first set, and I turned on the GoPro strapped to my chest. We successfully made it through the first two sets before getting absolutely crunched by a big wave curling laterally. Our timing was off so instead of gliding over the top, the boat immediately seized and rolled over to its left, flipping some into the water and trapping others underneath the boat.