Camp Parks Experiment: Grass Fire on Slope with Cross Wind.
A simple field experiment was conducted to measure and quantify fire–atmosphere interactions during a grass fire spreading up a hill under a moderate cross-slope wind. Observations from this experiment showed that convective heat generated from the fire front was transported downwind in the lowest 2 m and the highest plume temperatures remained in this shallow layer, suggesting the fire spread was driven primarily by the advection of near-ignition temperature gases, rather than by radiation of the tilted flame. Fire-induced circulations were present with upslope flows occurring during the fire-front passage helping to transport heat up the slope and perpendicular to the fire front. A decrease in atmospheric pressure of 0.4 hPa occurred at the fire front and coincided with a strong updraft core. These observations provide evidence that, even under moderately windy conditions, the pressure minimum in the fire remains rather close to the combustion zone and plume.
Prescribed fire experiment at camp parks, Ca July 2010. Ignition by Marin County fire crew.
Time series of surface pressure (red) and vertical velocity (blue, black) during fire front passage. Figure taken from Clements and Seto (2015). Strong updraft core occurs during a pressure decrease of ~0.5 hPa.
