Thanks to Grailknight, Surrealone, and Roter Baron. Here is my experimental power design.
Tidal Wave: Blast 12d6. Indirect (To reverse the direction of "Reduced By Range"; +1/4), 1/2 END (+1/4), Personal Power Immunity (+1/4), AoE: Hexes (64m; +1 1/4). 180 APs. Gestures with Two Hands (-1/2), Requires a Water-Bending Roll (-1/2), Limited Range of 64m (-1/4) Reduced by Range (-1/4) Concentration (1/2 DCV; -1/4). 65 RPs