Incredible tire pictures...

[70bigblockdodge]

You got a puncture last winter, it did not make the tire go flat but allowed salt/calcium water and oxygen to get to the steel belt wires. The wires (small diameter stranded cable) rust and eventually fails. If one fails you may just get a broken belt, if the elements get to multiple wires this will eventually happen. Freezing will separate the rubber further to include more wires.
This is why you see so many truck tires exploding in the spring. I have had many casings I thought would have no problem taking a cap till they ground off the tread and the belts start popping.
It just happens.
Actually, it is a flat tire that did not happen back when.

 

[65sporty]

Glad to here that your ok and it didn't happen at highway speed. I used have a Chevy Astro van and I ran the Mastercraft Glacier Grips on it. I had 8 wheels and would buy a new set for the winter run them 2 winters then leave them on and buy another new set in the winter. I never had one come apart because it was a winter tire run in the summer