tornado sim question

[Thomixioso]

Try to increase density of emitting smoke and tune smoke dissipation. You must solve the problem with velocity, that particles pushing smoke, it is important for keeping smoke on that path. Also play with opacity ramp of smoke, left side of curve is dissipating smoke, right side is thickest. So that right side you need to decrease.

Ps: You have to check stoke plugin for Max, this will help you a lot with tornado sims.