The powered glider was destroyed and the Airline Transport pilot was seriously injured at about 0940 Pacific time when the aircraft experienced an in-flight breakup during an unknown phase of flight. Visual conditions prevailed at the impact site; undetermined conditions existed aloft. The pilot had been cleared to fly in an airspace block between FL180 and FL280. Controllers opined that the pilots communications sounded normal during conversations within minutes of their losing radio and radar contact. The last Mode C radar hit was at 0939:30, when the glider was about 0.8 nm north-northeast of Sparks. One minute later the glider was about 2.2 nm and 032 degrees from Sparks. Air traffic controllers at the Reno/Tahoe International Airport reported observing a target rapidly descend on their radar. Using binoculars while looking in the same general area, they observed a parachute. The pilot, with his deployed parachute, was located about 1.6 nm and 007 degrees from the main wreckage. The Reno Airport is about 4.8 nm south of the accident site. At 0956, Renos reported weather included wind from 190 degrees at 29 knots with gusts to 38 knots, few clouds at 10,000 feet and broken clouds at 15,000 and 25,000 feet. Lenticular clouds were present in the area.