Were these initially forest fires? If so, why are there no quarter-mile wide firebreaks separating the forests from the home subdivisions?
The fire started in grassland, not forest. I'm not sure quarter-mile firebreaks would be enough given the high winds. Embers would probably be carried right over the firebreaks, although it might slow things down. The Marshall fire started in what is normally a greenbelt area between Boulder and Denver. I expect it's brown during drought, but in any case it's intended for recreational use and for preventing sprawl.