Diffuse streaks in the electron diffraction patterns of single‐crystal white tin films appear to be associated with nearby reflections, whether they are allowed or forbidden by the structure factor. Zero‐order streaks, also observed, as well as the forbidden reflections and their accompanying streaks, are interpreted as resulting from multiple diffraction events. The disappearance of the streaks in x‐ray patterns when the sample is cooled to −155°C suggests that they arise from an interaction between the incident radiation and very short wavelength elastic waves having highly anisotropic propagation.