National Geographic Readers have been a hit in the competitive beginning reader category, and this book follows upon that success with the same careful text, brilliant photographs, and the fun approach to the high-interest subject of weather that has proved to be a winning formula with kids. What causes thunder and lightning? How do different clouds form? What makes a tornado twist? Kids will discover the answers to these questions and more in this colorful, photo-packed book. In this inviting and entertaining format, kids will discover what causes the weather they experience every day. This level 1 reader is written in an easy-to-grasp style to encourage the meteorologists of tomorrow!