On July 4, 1997, at 1741 mountain daylight time, a Let Blanik L-13, N65378, was substantially damaged when it collided with terrain during landing at Pagosa Springs, Colorado. The commercial pilot was not injured, but the passenger sustained a minor injury. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under Title 14 CFR Part 91. The flight originated at Pagosa Springs, Colorado, approximately 1720. According to the pilot's accident report, he was towed aloft and released 1/2-mile north of the airport approximately 9,500 feet msl (above mean sea level). He was able to climb in a thermal to 10,700 feet, then proceeded east in search of other thermals. When the pilot was about 3 to 5 miles east of the airport, he realized he was at a "low altitude (about 9,700 feet) relative to the airport." As the pilot glided towards the airport, he encountered "moderate sinking...descent rate around 600 to 700 feet per minute. He began looking for emergency landing fields. The pilot soon realized he did not have sufficient altitude to glide to the airport, and elected to land on a school soccer field. During the approach, he noticed a 5-foot hill in the middle of the field. He decided to land on the other side of the hill. After touching down, the pilot applied "moderate braking." The aircraft went off the field and collided with an embankment next to a road.