This is an effects pack ($69) for Unreal Engine. Runs in real time and comes with a ton of assets:
http://www.digitaldracott.com/SubPage_ForestFire.php
And another that is not quite so 'hot':
http://www.digitaldracott.com/SubPage_Short.php
Very 'cool', but I mean it literally. That is some awesome effect.
Wow! Even sparks and debris.