I'm not sure - the Arkansas River is apparently flowing pretty good right now. Maybe a local will comment, but the river is not far from where Suzanne disappeared (and its headwaters in the snowpack are 27 miles away - so the water would be quite cold, it's at medium flow right now).
Daily Arkansas River Flow Report
So many rocks, tree roots and boulders, people go missing in cold water rivers all the time and are either never found or found much later, way downstream. I think there's a dam not far downstream, though, so they will probably check that area more than once.
I wish we knew if there was a reason for her to be distraught.