Reading today’s update from AKFireInfo about the Livingston Fire, it mentions smokejumpers setting up sprinklers around 5 cabins about a mile from the head of the fire. This is a common tactic for protecting isolated values at risk, but we did not have good information on how much sprinkling was needed and how long wetting down an area would last. Until now.
Devon Barnes, a graduate student at the University of Alberta, worked with BLM-Alaska Fire Service Fire Ecologist Eric Miller to measure the effect of sprinkling on interior Alaska feathermoss fuel beds. Their work found that it takes 0.8 inches (20 mm) of sprinkled water to bring the top 5 inches of duff to saturation. This takes about 7 hours of sprinkling with a Mark 3 pump at a low throttle, and uses about 2 gallons of gas. Devon and Eric estimate that the sprinkled area can resist ignition by firebrands and surface spread for about 3 days in typical summer weather. The area may of course dry more quickly in very hot and windy conditions.
You can find more details on the project and its results in this new AFSC research summary.