This was actually what I first encountered when I arrived at Amethyst Brook. I hadn’t noticed the way the water moved around the large rock previously. Maybe it wasn’t quite as noticeable until the water was so voluminous. Rocks do move over time aided by the push of the water and ice shoving them around.
Canon 70-200 f/2.8+CP, 2.5 sec @ f/11, ISO 400.