diff --git a/dive.c b/dive.c
index ea97833ea..2ed90f284 100644
--- a/dive.c
+++ b/dive.c
@@ -2911,6 +2911,10 @@ static int split_dive_at(struct dive *dive, int a, int b)
 			event->time.seconds -= t;
 		}
 	}
+	dc1->maxdepth.mm = 0;
+	dc2->maxdepth.mm = 0;
+	d1->maxdepth.mm = 0;
+	d2->maxdepth.mm = 0;
 
 	fixup_dive(d1);
 	fixup_dive(d2);