In April 2011, the worst tornado outbreak in decades left a trail of destruction across the U.S., hugging more than 360 people. Why was there such an extreme outbreak? How do such outbreaks form? With modern warning systems, why did so many die? Is our weather getting more extreme-and, if so, how bad will it get? In this NOVA special, we meet scientists striving to understand the forces at work behind last year's outbreak. Could their work improve tornado prediction in the future? We also meet people whose lives have been upended by these extreme weather events and learn how we all can protect ourselves and our communities for the future.

NOVA Season 39 Episodes...

• s39e01 - Engineering Ground Zero
• s39e02 - Surviving the Tsunami
• s39e03 - Finding Life Beyond Earth: Are We Alone?
• s39e04 - Iceman Murder Mystery
• s39e05 - The Fabric of the Cosmos - What is Space?
• s39e06 - The Fabric of the Cosmos - The Illusion of Time
• s39e07 - The Fabric of the Cosmos - Quantum Leap
• s39e08 - The Fabric of the Cosmos - Universe or Multiverse?
• s39e09 - Deadliest Volcanoes
• s39e10 - Bombing Hitler's Dams
• s39e11 - 3D Spies of WWII
• s39e12 - Mystery of a Masterpiece
• s39e13 - Ice Age Death Trap
• s39e14 - Separating Twins
• s39e15 - Cracking Your Genetic Code
• s39e16 - Hunting the Elements
• s39e17 - Deadliest Tornadoes
• s39e18 - Why Ships Sink
• s39e19 - Secrets of the Sun

NOVA Show Summary

Seen in more than 100 countries, NOVA is the most watched science based television series in the world and the most watched documentary series on PBS. It is also one of television's most acclaimed series, having won many major television awards, most of them many times over.