The pilot reported that, during the landing roll, the tailwheel-equipped airplane suddenly started a "sharp skid" to the left. He added that the airplane exited the left side of the runway, struck a large runway light box, and the left landing gear collapsed. Subsequently, the airplane came to rest nose down.

The airplane sustained substantial damage to the left wing lift strut.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.