You have cause and effect reversed. A loud explosive hole in a bicycle tube is always a result of the tube having escaped from the inside of the tire - either by the bead of the tire unseating from the rim or because a hole developed in the side of the tire. Once part of the tube is outside the tire it will rapidly blow up like a balloon and pop with a very loud noise like a gunshot.
In the OP's case I suspect that at some point in the past his tire sidewall was damaged by hitting a sharp object like a rock. Some of the cords in the sidewall frayed and eventually started to break due to the outward force of the air pressure in the tube. Eventually enough of them broke to allow the tube to expand out through the hole in the sidewall.