The Pioneer Fire grew dramatically this week, shooting its way through the Boise National Forest. In just two days, it burned more than 70 square miles. So far it has burned 281 square miles.
Despite more than 1,000 people working the fire, it's only 52 percent contained. And officials say it won't be under control until a major rain or snow event, probably sometime in October.
Why is it burning so fast? And so much? And why can't firefighters surround it? This video, from the Boise National Forest, gives a pretty good snapshot of what crews are facing on this megafire: