So here's the deal with frog rock, the kyakable lines are fairly easy straightforward, and not really to challenging. The danger of this rapid is the failure to make the move to the left at the end. The right side is bad news. It features two large undercuts with a sieve in the middle, I have heard of people swimming through this sieve and being ok, but unfortunately that is not always the case. Three people I know of have lost their lives to this hazard, all commercial rafters. One was a 12 year old boy who swam into the sieve after his raft flipped, and the other two were a couple of newlyweds who swam into the sieve after their raft flipped. Once in the sieve, little can be done to contact/recover the victims. In both cases of the fatalities, the water level was around 700 cfs and in order to enact the recoveries, water had to be shut off from upstream to a level of around 250 cfs. The hazard of this rapid is truly avoidable with proper skills, but most commercial outfitters in the valley tend to portage the rapid at lower flows due to the significant hazard. Right now would be a good time to go look at the rapid to see the featurtes I am taking about, and if it looks anything like it did last winter, the sieve/undercuts are full of debris, in other words a nasty place to be. Well, I hope this answers your question, but for the most part, it is an easy rapid with conqequences that can quickly become unsurvivable.