If the belt snaps, I usually see it snap with only a few fibers here and there and a bit of fiberglass dust, but when its shredded flat like yours is, there will be fibers and fiberglass dust everywhere, as you've noted.
That said, @
wqc3241 I suggest taking a can of compressed air to the small nooks and crannies of your engine bay to blow out the fiberglass and threads. Try and do it with the bottom shield off, so the threads and dust can fall down for easy sweeping. Otherwise, they'll just be sitting atop the tray, and will fall on you when you remove it.
Just some general questions if you have the time...
Did you install the KW supercharger kit, coilovers or headers yourself?
I see the bolts on the mounting plate are a tad rusty, how long did you have the kit on before heading to the track?
How long between track days?
How many sessions before it broke?
Were you running an oil cooler?