This is something that I've been working on over the past year or so (just on and off, between projects etc). I've seen a few other tutorials and presets on twisters but really nothing out there that is easily modifiable or accessible by others. Well I'm sharing this and I hope that most of you get some use out of it. Obviously you'll have to tweak the files to suit your needs and probably add on some effects to make it more realistic but its better than starting from nothing. The file is in both CS4 and CS5 After Effects and uses Particular 2.0
Please feel free to link back if you use the preset/pre-comp in a project of yours. I would love to see it.
You can get the files by clicking here: Tornado CS4 - or - Tornado CS5