How do I make sunlight emit between clouds? Many tutorials show how to make mist and have light go through a window and it's pretty straightforward, however, what puzzles me is how do you do that when you emit beams of light between clouds? 

If it's in the distant background I'd just use a HDRI or similar but I want the camera to fly into them. 

In cycles, what technique should I use to approach this shot? 

ADDITIONAL 
In the "possible duplicates" the rays don't pass through the clouds they emit off screen or through an object but never clouds. So how to make the emission of clouds have variable opacity in a specific pattern?
This has been asked before many times.

You need volumetric lighting to see beams of light shining through the environment

The reason you would see those rays in the real world is because all the suspended particles in the air (smoke or mist) reflect some light, making the air not completely transparent anymore.

Volume scatter simulates that effect.

Add volume scattering as volume for the world (or create a big box that surrounds the scene and connect a volume scatter node to the volume of the material shader as shown on this post). The default value of 1 is way to high, so bring it down a bit.

Add a lamp and give it a very high value for intensity.

Create a plane with a texture that controls the transparency.



IF you want a more elaborate scene, then create clouds with the cloud generator add-on. The important part is that the clouds create different degrees of opacity between the light and the ground