Fire Whirls

Fire whirls induced by a line fire on a windward slope: a laboratory-scale study

“…Extreme fire behaviour, characterised by rapid fire spread, intense burning, long-range fire spotting, fire whirl and unpredictable shifts etc., defines the new context of wildland fires (Castro Rego et al 2018;Tedim et al 2018). A fire whirl, also named a fire whirlwind, fire devil or fire tornado, is often reported to occur in wildland fires, due to the interaction between the burning flame front and the local wind field (Zhou 2018). It is not only related to the vortex containing flame but also to a whirl that appears in and around a fire containing smoke, hot gases, unburned fuel and ashes (Soma and Saito 1991).…”

“…Fire whirls can remarkably increase the fire spread rate and burning rate (Countryman 1971) and have close relevance to extreme fire behaviour (Wang et al 2017). Their appearance can result in serious difficulty in wildland firefighting (Countryman 1971) and induce great losses of life and property (Zhou 2018). Thus, the fire whirl phenomenon has occupied scientific and engineering research for decades, and is still a major concern.…”

“…However, the three conditions are too abstract to clarify the weather and terrain conditions that trigger different types of fire whirls. Accordingly, a concrete analysis has been suggested to clarify the formation condition and mechanism for a specific fire whirl (Zhou 2018;Zhou et al 2019). A reduced-scale experiment has been successfully used to explore the open-field ambient wind condition for fire whirls generated in the wake of mass fires (Soma and Saito 1991), in the vicinity of L-shaped fires (Soma and Saito 1991;Kuwana et al 2008), by the interaction of multiple fires (Soma and Saito 1991;Liu et al 2007) and over a line fire (Kuwana et al 2013;Zhou et al 2014Zhou et al , 2016Zhou et al , 2019.…”