A quick introduction to creating a hurricane or typhoon shape in Terragen. This video is part of an beginner tutorial series on Terragen 4.

Additional reading:

Procedural hurricane (credits to torebernhoft for node structure inspiration)
https://planetside.co.uk/forums/index.php/topic,26879.0.html

Image mask approach:
https://planetside.co.uk/forums/index.php/topic,3116.0.html
https://planetside.co.uk/forums/index.php/topic,3287.0.html