Suppression of smaller wildfires over the past century has changed forests in fundamental ways. “We’ve been so success­ful at excluding fire that forests are nearly continuous,” says Mark Finney, a researcher at the Missoula Fire Sciences Laboratory, who develops modeling software. Previously, when most fires were allowed to burn, wildlands were a patchwork of burned and non-burned areas. Without these natural breaks, fires can now grow much larger than they used to.

All of these factors combine to spawn what FBANs call “extreme fire behavior.” Behind Dawson, I see orange smoke mushrooming from a ridgeline high into the sky. Dawson tells me that this indicates a “megafire”—a capricious, un­tamable beast that frustrates FBANs. (Colorado saw two megafires in the first half of 2012 alone.) A megafire can create severe weather of its own, befuddling models. Gusty outbursts blow counter to prevailing winds, goading flames downhill when the models predict an upslope burn. Blistering heat flash-dries foliage. In High Park, Dawson told me, “we’ve got mixed conifer up there, but in places it’s burning fast, like chaparral.” Timber stands that models say will burn slowly erupt as if doused with kerosene. Rob Seli, also based at the Missoula lab, explains that many megafires are plume-dominated. And a plume-dominated fire, he says, is “like an atom bomb going off. It can expand rapidly, in any direction. It’s the same thing that happens in a thunderstorm. And models can’t account for this behavior.”

Some years from now, improved computing power will surely catch up to today’s fires, yielding models that crunch more variables with more elaborate characteristics—the flammability of different building materials, say, or the complex atmospheric physics involved in plume-dominated fires. (Even the fastest supercomputers we have now would take days to do this.)

In the meantime, some experts worry that younger fire analysts lean a bit too heavily on their data-crunching skills, and have little field experience. Dawson is thankful to have spent his early career fighting fires with an ax and a shovel. While working the High Park fire, he trekked into the field every morning to supplement his digital prognosis with some analog intuition. Tim Sexton, who is a strategic planner from the National Interagency Fire Center and worked alongside Dawson, also made a point of visiting the blaze. “The model gives you a place to start. But then go out and look at the fire,” Sexton says. “Because in nature, nothing is ever exact.”