Ewasko was last seen in Riverside County, California on June 24, 2010. He was planning a solo hiking trip in Joshua Tree National Park that day, and had packed a lunch, water and some snacks for his trip. He was supposed to return to his vehicle and call his girlfriend at 5:00 p.m., but he never did. She reported him missing the next day shortly after noon. Ewasko's rented white 2007 Chrystler Sebring with the California license plate number 6CVF834 was found at the park on Keys View Road. An extensive search turned up no sign of him. Temperatures at the park that week reached close to 100 degrees.

Ewasko lived with his girlfriend in Marietta, Georgia at the time of his disappearance. He is an Army veteran who served in Vietnam, is an experienced hiker who has visited Joshua Tree National Park on several previous occasions, and was in good physical shape in 2010 with no medical problems. He is presumed to have become lost or injured in the wilderness. His sons are attempting to have him declared legally dead.