In the paper, the authors described a discrete model of the nonlinear heat transfer process resulting from a local instantaneous ignition in a heterogeneous substrate, using elements of a cellular automata approach. As a result of discretization by a uniform grid, a flat area modeling a section of substrate is presented as an array of cells for which initial states are specified. As a characteristic of the state, we took the temperature difference between the substrate and the environment. One of the array cells is set on fire by an instantaneous impulse. We use a deterministic synchronous cellular automata. It is also possible to take into account the effect of temperature on the thermophysical properties of the substrate. Using the implementation of the described discrete model in the C ++ Builder environment, we performed heat transfer simulations for various substrate properties, boundary conditions, and source properties. The results of the cellular automata model qualitatively correspond to the physical concepts of the processes under consideration and make it possible to create a visual picture of the temperature profile evolution for the selected area of the underlying surface. The approach presented in the paper will expand the capabilities of predictive models in order to take into account the fire-hazardous characteristics of various types of soils.