Given this article, what is the largest size for a dead man zone?

Context: The dead man zone is the area directly around a bushfire that is likely to burn within five minutes given the current wind conditions or an anticipated change in wind direction. The distance this zone extends from the firefront is highly dependent on terrain, windspeed, fuel type and composition, relative humidity and ambient temperature, and can range from under 100 metres to well over 1 kilometre.

Answer: The largest size for a dead man zone is 1 kilometre