CAUSES OF THE 20 OCTOBER 1991 OAKLAND-HILLS CONFLAGRATION

The meteorologic and topologic causes of the 20 October 1991 Oakland Hills conflagration are described here qualitatively. A 3 GW example fire, 100 m in diameter, is used to show the impact of the 10 m/s wind and strong inversion layer at 600 m that existed on 20 October in contrast with the calm normal conditions that existed on 19 October. It is concluded that the dry, high speed NE wind, coupled with the inversion layer and the local topography channeled the hot products of pyrolysis and combustion, along with flaming debris, through a high fuel load region downwind and downslope of the initial fire, thus causing the unusually rapid initial fire spread and consequent conflagration.