There are numerous places in the Alberton gorge that can trap and hold a body. Now, with the river levels being at their lowest (currently today 1/1/22 @ 2200 cu ft/min), would be the time to go on a slow float on the gorge and have a look-see. Especially with a cadaver dog on board. Spring will soon bring high water levels and would most likely wash out any trapped drowning victims remains as body mass will have been significantly reduced do to decomposition allowing a release from its potential hold (sorry for the morbidity). Even at these low levels however, the attempt to float Alberton Gorge down river from where Rebekah's items were found on the beach isn't for beginners. Water temps are lethal this time of year and appropriate rafting skills and gear are required. I've been flipped twice on the Alberton but at much higher water levels. The recent cold snap we've experienced here will ice over sporadic parts of the river.
Cerb surfacing 10 miles down river from Rebekah's LKP (last known position) on the beach isn't all that unusual to me. I know several people consider this odd but I don't as I have intimate knowledge of this area. The lack of eddies and minimal "slack water" once entering the gorge, which is maybe a couple miles or so from the LKP, for something or someone to wash up in or on is minimal. Once in the gorge it's just that. A fairly narrow uninterrupted stretch of water with class II to class IV rapids. The timing would have been about right for Cerb to have been found. Being submerged and slowly moving down river undetected until given the warm water temps would have surfaced him several days later. The same would happen to a body unless it got trapped in the rocks along the way. Rebekah's PLS (point last seen) and her LKP was how long? We know Rebekah was at the beach via her video. Considering the location I would have to question the foul play scenario and deem it unlikely do to the exposure of an assault. Anyone passing by on the busy highway next to the beach can easily see what's happening there. I would expect a perp to seek its prey with less risk. I'm not saying it's not possible I just don't consider it likely. There are those crimes of passion the defy all odds though.
Unless someone was actually on the water, composing several rafts or kayaks floating over the surface going very slow and looking carefully into the water, the PoD or Probability of Detection would be minimal. A Heli finding a submerged person underwater flying overhead would be less than 5% is my guess and not much better walking along its banks. Most likely only 20% or less at best if floating with intent to search. Keep in mind when people are rafting or kayaking they're watching the surface of the water. Not what's underneath and in many cases not even what's on shore. I assisted in retrieving a body found by a fisherman out of the Alberton Gorge. It had been there for some time in the rocks and drift wood right along the shoreline. Countless rafters and kayakers had floated right past it for days and weeks but until a fisherman practically tripped over it it went unnoticed... My condolences to the family for their missing loved one and may 2022 provide the answers for which they are seeking. God bless you with courage and strength.