Firebrands spread fire efficiently, but their occurrence is difficult to understand and predict. It is obvious that potential firebrands form and burn-up continuously in any wildland fire, just as it is apparent that there is upward motion above a fire. But, firebrands do not always come out of fires in large quantities. If firebrand generation and lofting are separated into two interacting statistical processes with non-stationary means they can be treated as conditionally dependent, i.e. describable as a Markov process. This concept leads to a stochastic form of the Fokker-Planck diffusion-advection partial differential equation. It can be solved to demonstrate that firebrands are formed in a quasi-cyclic manner. © by the Society of American Foresters. Abstract reproduced by permission.