The article describes an attempt to estimate wave parameters from available data of the average and maximum wave heights impacted to hydraulic structures of the FPFC of St. Petersburg obtained from field observations. The methodology was developed to estimate wave heights of the set repeatability during storms, with application of the Monte Carlo method and method of the inverse transform of Smirnov. Convergence of the empirical and model distributions was checked by using the Kolmogorov-Smirnov criterion. Field data analysis shows some storms that took place within the observed period could be characterized by wave heights (h1 %) exceeding the designed ones.