  We study the maximum wave amplitude produced by line-soliton interactions of
the Kadomtsev-Petviashvili II (KPII) equation, and we discuss a mechanism of
generation of large amplitude shallow water waves by multi-soliton interactions
of KPII. We also describe a method to predict the possible maximum wave
amplitude from asymptotic data. Finally, we report on numerical simulations of
multi-soliton complexes of the KPII equation which verify the robustness of all
types of soliton interactions and web-like structure.
