Thunderstorm Facts



  • Thunderstorms begin when strong updraughts build up towering cumulonimbus clouds.
  • Water drops and ice crystals in thunderclouds are buffeted together. They become charged with static electricity.
  • Negative charges sink to the base of a cloud; positive ones rise. When the different charges meet they create lightning.
  • Sheet lightning is a flash within a cloud. Forked lightning flashes from a cloud to the ground.
  • Forked lightning begins with a fast, dim flash from a cloud to the ground, called the leader stroke. It prepares the air for a huge, slower return stroke a split second later.
  • Thunder is the sound of the shock wave as air expands when heated instantly to 25,000°C by the lightning.
  • Sound travels more slowly than light, so we hear thunder three seconds later for every 1 km between us and the storm.
  • At any moment there are 2000 thunderstorms around the world, each generating the energy of a hydrogen bomb. Every second, 100 lightning bolts hit the ground.
  • A flash of lightning is brighter than 10 million 100-watt light bulbs. For a split second it has more power than all the power stations in the USA put together. Lightning travels at up to 100,000 km per second down a path that is the width of a finger but up to 14 km long. Sheet lightning can be 140 km long.
  • Lightning can fuse sand under the ground into hard strands called fulgurites.
  • Few places have more spectacular lightning displays than Nevada, USA. The energy in clouds piled up during hot afternoons is unleashed at night.