Reverberation intensity fluctuations are not only important because they impact the performance of active sonar systems, but also because they may provide insight into the major scattering processes. In this article, a model for the fluctuations of signals backscattered from rough surfaces is developed, and its predictions are compared with high‐resolution bottom backscatter data. For reverberation due to Bragg scattering, the model predicts a unique dependence on beamwidth, which is supported by the data. A dependence on waveform, i.e., a frequency diversity effect is also predicted. This effect is, however, not unique to the Bragg scattering process.