A structure can be lost even when the main wildland flame front never touches it. Wind-driven embers may arrive before and after the front, enter vents or accumulate in receptive locations. Combustible fences, decks, mulch, vegetation and neighbouring structures can create continuous pathways. Radiation and convection can preheat or ignite susceptible materials when source geometry, distance and duration are sufficient. The engineering task is therefore to identify exposure pathways and receptor vulnerabilities, not to reduce the problem to one “safe distance.”