Murph’s Hole is a single feature rapid. It is a large hole in the right of center / center of the river after you come around a left hand turn. This is a big deal at high water so stay on your toes as you come around this corner and work hard to avoid it by hugging the inside corner left and pulling left. One nice aspect of this rapid is you can easily hike to it from Boundary Creek, so the day before, if you are done rigging and still have daylight, head down the trail for a quick scout.
Murph was a sweepboat driver that flipped here. That should give you some perspective at how large this feature can get.
At lower flows, the hole is not an issue.