Smoke coming from dashboard vents- Help

Any idea what to look for- My 82 Cordoba is not used very much anymore. But yesterday, I drove it for four or five hours. Everything was fine. This morning, almost as soon as I started driving, I noticed a burning smell in the car, then saw smoke coming out of the passenger side air vents. After turning off the motor, I opened the hood. Smoke was coming out of the cowl intake vent. I drove the car home and parked it in the driveway. Any idea of what could be wrong? Thank you.
Author: Yellowdart69