On November 28, 1999, about 1640 Eastern Standard Time, a Schempp-Hirth Discus A glider, N117TB, was substantially damaged during a forced landing near Palmerton, Pennsylvania. The certificated private glider pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under 14 CFR Part 91. According to a Federal Aviation Administration Inspector, the pilot departed the Beltzville Airport, Beltzville, Pennsylvania, under tow, for a local flight. While ridge soaring, the pilot elected to delay his landing back to the airport. The sun became low on the horizon, and the glider began to loose lift. The pilot attempted to fly the glider close to a ridgeline in an attempt to gain lift, but could not locate the ridgeline due to a glare through the windscreen. The glider began to descend and the pilot performed a forced landing to a parking lot. Approaching the parking lot, the left wing struck a tree, spinning the glider to the left. The glider then nosed into the ground, coming to rest upright. The sun set below the horizon at 1637.