In the context of the Swiss railway noise calculation model sonRAlL a model to predict sound exposure level spectra for reflections from cliffs was developed and validated with measurements. It is an engineering model with low computational cost that is applicable to any type of sound sources. The scattered energy reflected from the cliffs is modelled by the superposition of secondary sources placed on the cliff surface. The only free parameter of the model, the scattering coefficient, was determined by measurements with detonations of 200 g TNT e q in the alpine part of Switzerland. Measurements yielded good agreement not only in situations with reflecting cliffs but also in the presence of large boulder fields.