Smoking A/C pulley

Hi there, I have '98 escort that shut off on me yesterday when driving back from San Diego. My friend and I noticed a scent that smelled like something burning. No lights had came on before the car shut off. When I pulled over I noticed smoking coming from the engine bay. When I popped the hood I saw smoke coming from down low so I looked under the car and saw that a/c pulley was smoking and melted the serpentine belt and snapped it in front of my eyes. I did have the heater on if that has anything to do with it. Do you know if I have to replace the a/c pulley or is there possibly a different problem why this has all happened.