Well you heard a "pop" and not a "bang" so you didn't have an explosion, you had a puncture. That means you didn't have a casing tear and the tube didn't blow out. Somehow, something got to your tube and somehow the effect was delayed and somehow it did the damage when the bike was not moving.

The puncture could be a very small thorn or piece of wire or burr on the rim - check the inside of the tire in the location of the tube failure.

The delay effect could be caused by a change in temperature maybe... just a guess.

Usually an uncovered spoke head would cause an immediate failure, so I think that's an unlikely cause but easy to check for.