On July 5, 2002, about 1400 eastern daylight time, a Burkhart Grob G103 Twin Astir glider, N4446W, was substantially damaged after it landed short of runway 07 at the Ridge Soaring Gliderport (79N) Unionville, Pennsylvania. The certificated commercial pilot and the passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. In a written statement, the pilot stated that when he was on left downwind for runway 07, he saw a tow plane and a glider taking off on runway 25. The pilot had elected to land on runway 07 because it was the runway he had used to depart earlier, but the winds had changed and the runway in use at the time was runway 25. When he turned on final approach, the pilot realized he was getting close to the tow plane, and ducked under it to avoid a collision. The avoidance maneuver resulted in the glider landing short of the runway, and subsequently colliding with a ditch. A witness observed the glider when it was on short final approach to runway 07. He said the glider appeared low and touched down short of the runway in a field with crops about 2 1/2 feet high. The glider traveled about 20 feet, then hit a ditch that separated the field from the approach end of runway 07. The left wing of the glider came up and the glider pivoted on the right wing. The tail boom fractured, but remained attached to the airframe by pushrods. The witness also noted that the winds were from the northwest at 5 to 10 knots. The pilot reported a total of 8,000 flight hours, of which, 300 hours were in gliders. He also reported that there were no mechanical anomalies with the glider. Two Federal Aviation Administration (FAA) inspectors performed an examination of the glider. According to an inspector, the fuselage was fractured aft of the wings. Weather at University Park Airport, State College, Pennsylvania, 4 nm southeast, at 1347, included winds from 360 degrees at 8 knots, and visibility 20 statute miles.