From the Source:
"'This was an unusual year, and so part of this may be due to just the fact that it was an unusual year, and part of it may be due to the growing footprint of the wildland-urban interface,' Rideout says.
That interface is where homes and even whole cities are being built into the forests, and it's where most of today's high-profile fires happen — Yarnell Hill included. The homes in these zones are being built safer, and Rideout says that comes with some unintended consequences.
'As we take measures to try to make the wildland-urban interface a nice and safe place to be and to occupy, the incentive for it to grow gets even larger, so it's kind of a self-perpetuating situation,' he says."
Above: "The wildfire in Yarnell, Ariz., last June destroyed homes and killed 19 firefighters. Experts say expansion into wildfire-prone areas has created new challenges for firefighters." Courtesy of NPR.