As long as it wasn't buried too deeply

Apparently people came back to Pompeii after the Roman era eruption. Some buildings were taller than 20 feet, so a few things would stick out and mark the place clearly. Scavenging might be possible in somewhat sheltered areas, and I'd guess there would have been some rites possible for the already-buried dead family members.

And in a few years the land nearby would be fertile. Rain would tend to thicken and eventually harden the ash, so the window for digging might not be very long. But there'd be some worked stone handy.