A large region of central and western Canada experienced a particularly severe forest fire season during 1980 in terms of the number of fire starts, area burned, and suppression expenditures. In Alberta, most of the fire occurred during April and May in the northern half of the province. A total of 1356 fires burned over 639,807 ha. This represents 1.5% of northern Alberta (defined here as roughly the area above 54 degrees N latitude). Fire protection costs, fixed and variable, totaled 46 million dollars in the province. There were 42 'Class E' fires (>200 ha) in Alberta during the 1980 fire season. The purpose of this paper is to document the environmental condition associated with the extreme behavior exhibited by a single Class E fire during its first burning period. The particular fire under examination here, referred to in the official records of the Alberta Forest Service (AFS) as DND-4-80, occurred in the Cold Lake Air Weapons Range and Lac La Biche Forest of east-central Alberta (Fig. 1). On May 2, 1980, it advanced nearly 18km to the north from its point of origin, in a period of five hours. The fire eventually covered an area of 137,313 ha in Alberta and an estimated 40,500 ha in Saskatchewan (referred to in that province as Victor Fire). The initial run of DND-4-80 Fire was selected for a case study analysis because of its rapid rate of spread and the availability of a rather complete set of weather data.