Description

INTRODUCTION: Fire in the interior basin of Alaska is commonplace. Lightning- and man-caused fires have burned and reburned millions of acres. Despite their commonness and extensiveness, the specific history and characteristics of a fire as the relate to fules and weather have not been systematically observed and recorded. The Hughes fire in July 1962 did provide an opportunity to make systematic and detailed observations on fire behavior, weather, and fuels. The results of those observations and measurements are the basis of this report. The information and knowledge gained from this and similar opportunities as they arise will aid the fire control manager to more accurately predict fire behavior and, thereby, increase the effectiveness of the control techniques he uses. The assistance and cooperation of the Bureau of Land Management is gratefully acknowledged and, in particular, that of George Kitson, fire boss for the Hughes fire. CONCLUSION: Daily weather is a dominant factor influencing the flammability of interior Alaska's forests, particularly in areas where lichen-moss fine fuels are abundant. During relatively wet seasons, periods often occur when the relative humidity falls below 40 percent. Wildfires, burning in lichen-moss fuels, can be expected to rapidly increase in size during these periods. Conversely, these fine fuels become difficult to ignite soon after the relative humidity rises above 40 percent. The water content of lichen-moss fuels is apparently very sensitive to changes in atmospheric moisture.