Thunderstorms develop when thermal updrafts create bands of negatively and positively charged particles within a cloud. When the insulating air can no longer contain the charges, surges of electricity flow between the different regions. Intra-cloud flashes are lightning strikes between different layers of a cloud. Cloud-to-ground lightning occurs when electrical surges flow to the ground. Lightning may strike as far as 10 miles away from the center of a storm, even in areas with relatively clear skies and no rain.