Logging slash on a 486 hectare site in Ontario was burned as part of a Forestry Canadaforest management program.A 100hectareportion of this site was instrumentedbyseveralgroups interested in large scale fires. NIST utilized Forestry Canada data on mass loading before and after the fire, total burningarea as a functionof timeand burningduration to estimate the spatialand temporalpatternof heat release during the burning of the instrumented section of the fire. The heat release rate was estimated to reach 2-4 x 107kW during the time of interest, This information was utilized in the context ofa flow model due to Baum and McCaffrey to calculate the near-ground flow field induced by this heat release pattern; the results compared moderately well with point measurements made in the field.