The roar of the Roaring Fork

The Roaring Fork River starts as runoff from the western side of Independence Pass collects in that boggy area in the picture below. (I don't often knowingly see the headwaters of anything.) Farther along, having grown considerably in size, it has to squeeze through this gap.

Here's a view with a fellow photographer in it for scale.

The area is called the Grottos, because this is what it looks like after the runoff and before it freezes over.