The buggered sidewall
The spare in place
I suspect the hole was made by some bit of trash left in the desert by human trash.
Now, here's a challenge for GM engineers. Completely flatten a rear time on an Express or Savana, then try to get the spare out from under the van. No fair jacking up the van first, because it would dangerous to get under there with only the factory-supplied scissor jack. Oh, and you're on rocky ground. And it's about 55 degrees. (Not cold, but not pleasant.) Having fun yet?
Luckily, this flat happened just outside a city with several tire buying options. And with friends to watch me change the tire while offering their condolences. That's the proper way to do things like this.