The flight instructor of a glider report that, during landing, about 100 above the ground, a "a sink rate started to develop". He added that, he took over the flight controls and closed the spoilers. The glider impacted the airport perimeter fence and landed short of the runway, then slid into a culvert.
The glider sustained substantial damage to the empennage.
The flight instructor failed to submit the NTSB Form 6120.1 Pilot/ Operator Aircraft Accident/ Incident Report.