AC Caught Fire?

I have a 2002 Dodge Grand Caravan Sport..Yesterday on my way home
from work I had the AC on. After about .25 miles I heard a low moaning
sound from the passenger side for about 3 seconds, then it stopped. I went
on, not knowing what it was, car was running fine. Then another .25 miles
further I smelled a burning smell like rubber or plastic. I wasnt sure if it was
outside somewhere or my car. Then I saw the white smoke coming out
from under the hood. I pulled over in a field and shut everything off. I
opened the hood and smoke came out from under the alternator
somewhere I could not see, on the passenger side. It finally slowed down
then stopped. Very scary! I check all fluids and they were fine, engine was
not hot either. I was figuring it to be something with the AC, compressor
must be under there. I started it up again without AC running, it was fine.
So I drove on home. So... what caused this? Was it the clutch or
compressor? What happened that it would do this? What should I do now?
Thanks!