Federal agencies use drones to map fires, find hotspots and ignite burns, and researchers are testing robots on rough terrain and artificial intelligence in fire and smoke behavior forecasts.By Mosabber HossainDuring the Sand Creek Fire, which has burned since the start of August in southwestern Montana, difficult terrain and fire-weakened trees posed hazards to crews searching for areas still smoldering on steep slopes after the blaze passed. So instead of relying only on firefighters to find hidden embers, fire managers used unmanned aircraft to seek out heat sources.