Landers was last seen near Lake Helen in Siskiyou County, California on May 22, 1999. He planned to climb Mount Shasta and was carrying a backpack full of food and water. He complained of feeling ill and left camp at 9:00 a.m., ahead of his two climbing partners, to get a head start. He has never been heard from again. Landers is an experienced hiker, mountain climber and distance runner, and was in good physical shape in 1999. An extensive search of the mountain turned up no sign of him.

Landers lived in Orinda, California at the time of his disappearance, and had formerly served on the town's school board. His case remains unsolved.