kyle dickman: we were really good at it. firefighters could put out 99% of fires before they grew bigger than an acre. paul hessburg: and from about 1935 to about 1985, you see not much fire burning. and it made our fire suppression look great. steve pyne: and that was a very poor judgment. well, they completely misjudged the character of the overall fire scene. paul hessburg: what's happened since the exclusion of fire is forests have gotten denser. the forests of today look nothing like they did in the 1930s. there are 10 times even more trees than that on the landscape of the historical condition. and they will burn bigger and they'll burn hotter than they burned historically. and what we didn't know in those days and we've learned later through research is, fire is medicine on the landscape, and it's how we can live safely. and here's why that's so critical. it was the frequency of the small- and medium-sized fires that blocked the flow of very large fires. you might burn out a patch in a forest, but the bulk of the forc

kyle dickman: they use chainsaws a lot. brendan mcdonough: you're removing everything for miles on end. so if that tree is 60 feet tall, you're cutting that entire tree down. it's not for the faint of heart. sometimes we do use fire to fight fires. kristen honig: using drip torches to burn the fuel in a controlled fashion so that by the time the main flaming front got there, there would be no more fuel for it to burn. and that would stop the fire's advance. todd abel: a lot of times, we'll do a lot of those firing operations at night, where we have better control over what that looks like. kyle dickman: so june 30, the yarnell hill fire is just ripping to the north. and the priority is to stop this fire on the northern edge. and we start hiking in. we were on the fire's edge. the flaming front was two to three miles long. probably had 20-, 30-foot flame lengths. kyle dickman: jesse steed asked brendan "donut" mcdonough to act as a lookout down in the valley below the ridgeline. brendan mcdonough: and i hiked into my lookout