Series showing how new camera technology is revealing the inner workings of the Earth's most spectacular natural wonders. Dr Helen Czerski examines the extraordinary new images - from eyewitnesses, scientists and film-makers - that are transforming our understanding of how and why these phenomena form. In this episode Helen peers into the heart of the storm to find out how advances in technology are giving new insight into tornadoes - the fastest winds on the planet. From the breathtaking footage that capture the extreme weather events that produce them, to the latest experiments investigating their incredible destructive power, Helen discovers how understanding the subtle changes deep within the storm are improving predictions of when and where these devastating beasts will strike. episode 5.