Rock

Matthew Cooper here:

The super high water (about 9000cfs) of late June washed away a lot of the trees that were above the dam. This changed the features of Box Wave and Winnebago Wave significantly. Box Wave is way more powerful, and more of a hole. Winnebago wave is no longer a wave but a very powerful, very keepy holem that is very ugly at 5000cfs. Shucks!