The pilot reported that during an aerial application flight in rolling hills in a canyon, the canyon wind forced the airplane to the ground. The airplane impacted terrain, the pilot egressed from the cockpit without further incident, and a postcrash fire occurred. The airplane was destroyed in the postcrash fire. The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. ADDITIONAL INFORMATION Mountain Flight Operations The Federal Aviation Administration has published FAA-P-8740-60 Tips on Mountain Flying. This publication provides various tips on how to conduct safe flight operations in mountain areas. This publication states in part; Strong winds can cause some of the most dangerous conditions you'll have to contend with in the mountains. To minimize the chance of encountering dangerous turbulence, mountain flying should not be attempted if the winds aloft forecast at mountain top levels are greater than 25 knots. Above this level, potentially dangerous turbulence, as well as very strong up and down drafts is likely.