Does lightning travel from the earth to the sky, or from the sky downward? Lightning travels both ways. Lightning is a huge electrical discharge that results from vigorous motions that occur in thunderstorms. Lightning can travel from cloud to cloud, within the same cloud, or between the cloud and ground. In-cloud lightning discharges are more common than cloud-to-ground discharges and are not as hazardous. Cloud-to-ground is the best known type of lightning and it poses the greatest risk.