All the regular wave theories are suspect for breaking or near breaking waves. In deep water the height of a breaking wave, $H_\mathrm{B}$, is commonly taken to be $0.14 L$, where $L$ is the wave length. An expression which covers all depths, due to Miche, is
\begin{equation} \nonumber
H_\mathrm{B} = \frac{0.88}{k}\ \tanh(0.89 k d)
\end{equation}
where $k=2\pi/L$ is the local wave number as calculated by Airy wave theory and $d$ is the water depth at the seabed origin. OrcaFlex reports a warning if the wave height exceeds this breaking wave height.
