Hi everyone
In maya i used stroika plugin so making Tornado is easy .In Follow field we can move particles on surface.but Houdini follow field is totally different.

How to move particle's on surface without using creep (behavior) ?

there's a step by step tutorial about tornado at 3dbuzz, under Houdini/effects

Take a look at this example as well.
It used a ray sop to project a point onto the surface. The nice thing about this is that you can then interactive (with the Locator object in the example) direct where the tornado touches the ground.
The only tricky part is in the pop network, creating one active particle as the target for the orbit.
There's a switch pop in there that allows you to choose from three methods. The first option is a static location, using a location pop.