The glider pilot's inadequate en route planning, which resulted in a forced landing in an area without suitable landing terrain. Factors include no suitable landing terrain in the area where the pilot found it necessary to execute a forced landing, and trees at the location where the aircraft came in contact with the terrain.

The pilot's failure to maintain directional control of the glider after its wing came in contact with long grass growing on the runway surface. Factors include the pilot's improper decision to attempt a landing on a runway with known directional control hazards, and long grass present on the runway surface.