According to the glider pilot, the flight was intended as a local recreational flight. He planned to climb via thermals to get across a five-mile gap between ridges, but was unable to gain altitude. He then attempted to turn to a "spur" that was separate from the main ridge to gain lift, but while performing the maneuvers the glider continued to lose altitude in a downdraft. The glider subsequently impacted trees and came to rest inverted, seriously injuring the pilot. The pilot reported that there were no mechanical problems with the glider. He stated that, in retrospect, he should have released the 10 gallons of water ballast in each wing and deployed positive flaps. A weather observation taken 35 miles from the accident site, approximately at the time of the accident, recorded the wind from 301 degrees at 13 knots, gusting to 20 knots.