Realistic Tornado Clouds

How could I make a similar material for a particle system similar to whats in the image below? I have been experimenting with several cloud/smoke/mist/fog materials in different example projects but I just can’t seem to get mine to look anything similar to this. Any advice or help would be greatly appreciated. (Sorry for the bad quality of the image. Here is the video: https://vimeo.com/54135009)