Iain Stewart travels across mountain ranges and glaciers to reveal ten remarkable stories about avalanches. Over a million avalanches happen each year, and yet we know more about the surface of the moon than we do about the chaotic turbulence inside an avalanche. We discover how the deadliest avalanche in history killed 18,000 people in 3 minutes, how Hannibal's army was devastated by avalanches as he crossed the Alps to fight Rome and why an avalanche was key to a great aviation mystery.