Island Mountain is typically the largest and most technical rapid on the run. While it is straight forward at lower flows, higher flows bring on big waves and hydrolics that can flip boats.
The rapid can be scouted from the railroad tracks on the left bank above a large cobble bar. At ~5,400 CFS, there are multiple routes through the rapid, most of which have much stronger eddy lines and currents than appears to be the case from high on the bank where people scout the rapid.