Cloud to ground or ground to cloud?

It's a question we often get concerning lightning, and the answer is "yes". Here's why.

As a thunderstorm builds, and the electrical potential between the cloud and the ground increases, lightning results to drain off the electrical energy.

The initial stroke is from the cloud to the ground. It's called the "step-leader". This invisible channel heads downwards, looking for a place to make contact with the earth. It tends to connect with the tallest object in the vicinity.

After the connection has been made, the "return stroke" or "return flash" is the result. It goes from the ground to the cloud, and is the bright ribbon you see in the sky...so the final answer is, th lightning process goes from the cloud to the ground and from the ground to the cloud, but the part you see is from the ground to the cloud.