DEN90FA022

The plt & pax intended to look ovr property & look for moose. The plt rprtd they flew up & down svrl canyons at alts BTN8000 & 10,000 ft MSL. Shortly after entering a 45 deg bank turn for a 2nd pass over an area, the plt heard a 'muffled pop' that he believed had come from the fwd part of the acft. He said he noted a fluctuation of the manifold pressure & believed he had an eng prblm. At about that time, the acft hit trees & crashed on snow covered terrain. Density altitudewas aprx 11,000 ft. the rear seat passenger (with only minor injuries) walked 6 mi for help. An investigation revealed the initial impact occurred when the right horizontal stabilizer hit a tree at aprx 35 ft AGL & 460 ft from the final resting place. The acft then flew aprx 300 ft, where the left wing tip hit a 2nd tree. Beyond the 2nd tree, the prop had severed numerous tree branches. The rear seat passenger stated the acft was circling at low alt; she didn't hear any change in eng sound, but heard the stall warning just bfr crashing. No preimpact part failure/malfunction was fnd.