Grays Grindstone

This rapid is probably the most fun on the Tuolumne. It's about half a mile long and full of rocks, holes, and waves. At lower water (below 1500 cfs), it's a zigzag between rocks and over drops. At about 2500 cfs, a big hole appears at the entrance on the right. You can skirt this hole by running a technical left route. At flows above 4000 cfs, this hole can easily flip rafts which would lead to a long swim.