It's surprisingly easy for the rear wheels to go out of alignment. The first time, the rear wheel rubbed through and blew out. The second time, a tow truck hooked to my rear wheel to pull me out of the ditch. I found out a bit later that the tire had worn through and blew out. I had checked it earlier for heating, but it remained cool. This is not a reliable method for determining whether your wheel is out of alignment.
It sounds like you’ve learned the hard way that rear wheel alignment isn’t something you can reliably check just by feeling for heat or inspecting visually. Misalignment can cause uneven tire wear and sudden blowouts, like you experienced. Even if the wheel feels cool, it can already be under stress or rubbing in a way that damages the tire. The safest approach is to get a proper alignment check at a shop—especially after incidents like being pulled out of a ditch—so you don’t risk another blowout or damage to the vehicle.