Alright, here are some figures if Penance wants to use them:
Going up a rope with a wall to brace against is DC 5 if you're moving at 1/4 speed, or DC 10 if you're moving at 1/2 speed (ie, 15' per round). If the rope-climbers can take 10, and the wave arrives at the end of the second round of Luhal's meddling, the only person in any danger is the last climber (Iando), who might still be too low to avoid the - well, waves is too calm a term for the turbulence this river tsunami will generate.
The guys with Spiderclimb, Heclar and Luhal, can do 20' per round from the time they start up the wall. Assuming Heclar takes a round to sort out what he needs to do (no offense intended, it's just that a hawk swooped down and turned into Luhal, who then cast a pagan spell on him and started barking orders, and I assume this is a bit startling), both Heclar and Luhal can be up 15-20 feet by the end of the second round.
I _think_ everyone's safe, if only by a fingernail.
-Albert