Abstract
This paper presents a model describing the flow field due to a two-dimensional infinitely long heat source in a stably-stratified atmosphere with a uniform wind cross-flow. The governing equation which is valid for any wind shear is non-linear in its general form and is solved for uniform flow only. The energy equation is not solved but a “source” function is assumed. The results of this model exhibit some of the observed mass fire characteristics such as the inflow window, the pinch effect, the upstream downdraft and a strong dynamic convection column. Blocking and the formation of eddies are shown to be the most important characteristics of the onset of mass fire conditions.