Sounds like it had a separation in the sidewall.
I’ve seen aircraft tires blow but they are a lot
higher pressure. I worked in the tire shop at
NAS Atlanta and was always leery inflating those
things. We always used a cage of course but still.
My thoughs and prayers go out to her husband
and family.
Eternal Father...
That might have been part of her mistake. She wasn't sufficiently respectful of the car tire's relatively low pressure.
I've been guilty of that, myself.