We got off the Main on the 25th, and my boat was one of 4 that I know of that incurred major damage at Mallard. I ran the typical left side run, though tighter to the left rock than the Mallard rock. However, I didn't even graze the rocks on the left bank, though was probably within a couple feet of them. As a former Main Salmon guide, this is a run that I've run dozens of times with no issue (and of course I've had lots of much worse runs as well!
. As I dropped through the slot, approximately 25-30 feet below the drop I heard/felt a rock rub, and sounded like left front. We were camping at Big Mallard camp and as we pulled in we found Idaho Afloat with two badly damaged boats upside down on the beach working on patching. As we were pulling in we noticed the damage to my boat as well and hightailed it to the beach. The damage occurred in the left rear tube, and was a total of five gashes ranging in length from 1.5 to 7 inches. All three boats there had nearly identical damage.
As we worked on repairs, a member of our group took a paddleboard across and hiked up to the slot to see if we could tell what the issue was. He reported a fresh scarp on the hillslope and a jagged, shark fin rock along the left bank. Apparently this rock was just coming into play as water levels dropped, and may or may not continue to be an issue for weeks to come.
Lots of boats made it through without issue prior to and after our incident, so the left run can still be made, particularly if you are closer to the Mallard than the left bank. There is of course multiple other runs at this flow further right of the Mallard rock.
My advice is either run right or scout and make sure you walk all the way to the bottom so you can be sure of the status of this hazard.