Serpetine belt ripped in half

Yesterday when I started up my 2006 X-Runner, it made a terrible squeal and I smelled something burning. Considering this is my first manual, I thought it was the clutch at first, but I lost power steering, the battery light came on in the dash, and the engine started to overheat.
I opened the hood and noticed that my serpentine belt was not loose, but it was actually ripped in half.
There was burned pieces of the belt on the ground, and on one of the idler pulleys the belt was melted to it. If I recall, it was the idler pulley between (near) the crankshaft and AC compressor.
It has 122k miles on it, and the belt did show signs of old age (dried out to a degree).
I am thinking something seized to ripped the belt in half. Are there "typical" issues with the 2006 regarding fan clutch seizing, etc? Or given the age and miles it could be any of the pulleys that could have seized?
Any insight would greatly be appreciated. Thanks!

 

Just a guess, but I bet nothing is wrong except the belt finally gave up. Part of it may have been fraying and got caught up in something it other.

It is possible a pulley seized, but you could just reach in there and check them out.

 

I already had it towed. I am a little disappointed in myself, because it really looked like a simple fix. I have the tools, and I have done work on my Mustang (racing fan install and Fluidyne radiator). I am oversensitive to overheating because my old Civic gave up the ghost that way.
I did spin the pulleys, but none of them seemed stuck.

Hopefully, it's just an old belt.

 

If they all spun easily and you didn't feel any side to side play, it's probably just the belt.

I did mine last fall when one started squealing. The alternator belt came apart lengthwise when I pulled it out. Just be happy you weren't out on the interstate or something.