Golden State Warriors head coach Steve Kerr is shattered over the L.A. fires that destroyed his childhood home ... saying it's "unfathomable" to think the place that held so many memories is gone.
Kerr met with the media ahead of Thursday's matchup against the Detroit Pistons ... and addressed the earlier reports that his old home -- where his mother still resided -- did not survive the Pacific Palisades blaze.
Kerr said his mom, Ann, is safe .