Severe Storms

What causes a calm day to suddenly turn violent, or even deadly, and why do some storms live on for hours or even days? Learn about the development of thunderstorms, blizzards, and hurricanes. Play the Cloud Lab: http://www.pbs.org/wgbh/nova/labs/lab/cloud/ Find discussion questions for this video and other resources in the Cloud Lab collection on PBS LearningMedia: http://www.pbslearningmedia.org/resource/nvcl.sci.earth.severe/clouds-and-severe-storms/