Description Water vapor in the air can cause clouds to form close to the ground. This is fog! Learn about fog and how people can stay safe when this type of weather is in the forecast. Fully decodable text features high-frequency words, and words with the f, hard g, and short o sounds. Also features tips for teachers and caregivers along with additional information at the end to build the reader's background knowledge of the topic. Downloadable Teacher Notes available.