Apparatus and associated methods relate to predicting precursor to coating spallation. Heat is provided to a first surface of a member. A time sequence of thermal images is captured of the first surface and/or a second surface of the member. Each of the images includes a two-dimensional array of image data. Each of the image data of the two-dimensional array of image data corresponds to an xy-coordinate pair. A two-dimensional array of thermal diffusivities is calculated based on the captured time sequence of thermal images. Each of the thermal diffusivities of the two-dimensional array of thermal diffusivities corresponds to the xy-coordinate pair. Each of the calculated thermal diffusivities of the two dimensional array of thermal diffusivities are compared with a predetermined threshold. If the calculated thermal diffusivity is greater than the predetermined threshold, then precursor to coating spallation of the thermal barrier coating at the corresponding xy-coordinate pair is predicted.