David left Curry Village early on Memorial Day, 1998, for a solo hike to Half Dome. He and his girlfriend agreed to meet back up at the trailhead later in the day, but he didn't show. His girlfriend reported him as a missing overdue hiker a few hours later and called his parents at approximately 10 p.m. that evening. A full search was initiated in the early morning hours of the following day when his girlfriend reported him missing again to a ranger who was in Curry Village.  

He was last seen by Outward Bound group hikers in Yosemite Valley en route to Half Dome. He asked the direction of the trail to Half Dome, and cloud cover was reportedly low. 

His mother and stepfather arrived the first day of the search and his father and brother arrived after the search began. After a week of the search, it was called off. 

Press coverage and search report related to the case:

May 27, 1998 San Francisco Chronicle, Missing Yosemite Hiker Sought
https://www.sfgate.com/news/article/missing-yosemite-hiker-sought-3086985.php

May 30, 1998 San Francisco Chronicle, Search to be Limited for Missing S.F. Hiker
https://www.sfgate.com/news/article/search-to-be-limited-for-missing-s-f-hiker-3004752.php

May 31, 1998 San Francisco Chronicle, Search for Hiker Scaled Down
https://www.sfgate.com/bayarea/article/search-for-lost-hiker-scaled-down-3087172.php

May 31, 1998 July Operations Report from China Lake Mountain Rescue Group - report by Linda Finco re: May 28-May 31 support they provided to Yosemite Search and Rescue
https://www.clmrg.org/taluspile/TPJuly98.html

Nov 5, 2018 Your Central Valley Yosemite Cold Cases Article and video story where Susan Quinn (David’s mom) is interviewed
https://www.yourcentralvalley.com/news/yosemite-cold-cases/