Lightning and Thunder

• Lightning and thunder are dramatic displays of atmospheric electricity, closely related phenomena occurring during thunderstorms.

Lightning

• Lightning refers to a sudden, massive electrostatic discharge between electrically charged regions within clouds, between clouds, or between a cloud and the ground.
• Lightning requires an immense potential difference, typically millions or billions of volts.
• Its high voltage overcomes air's insulating properties.
• Charge separation within a thundercloud involves collisions between ice crystals, graupel (soft hail), and supercooled water droplets.
• Heavier, negatively charged particles sink to the lower part of the cloud, and lighter, positively charged particles rise to the upper part.
• This intensifies the electric field as more charge accumulates.
• When the electric field becomes strong enough, it overcomes the air's resistance, and a lightning discharge occurs.
• Lightning includes:
  • Cloud-to-ground (CG) lightning: Striking Earth's surface and the most dangerous.
  • Cloud-to-cloud (CC) or intracloud (IC) lightning: Occurring between different clouds or within the same cloud.
  • Cloud-to-air (CA) lightning: Discharging from a cloud into the surrounding air.
• Cloud-to-ground lightning typically begins with a stepped leader, a negatively charged air channel that zigzags downward from the cloud.
• Positively charged streamers rise from objects like trees, buildings, and people as the stepped leader approaches the ground.
• A continuous channel forms when a streamer connects with the stepped leader, and a return stroke of intense current surges upward.
• The return stroke produces the bright flash that is seen.
• A single lightning flash may consist of multiple strokes, following the same channel in rapid succession.
• A lightning channel can reach up to 30,000 degrees Celsius (54,000 degrees Fahrenheit).
• Lightning strikes involve:
  • Electrocution.
  • Fires.
  • Power outages.
  • Damage to property.
  • Wildfires.
• Lightning protection measures include:
  • Lightning rods.
  • Surge protectors.
  • Awareness and precautions.

Thunder

• Thunder comes from the rapid heating of air around a lightning channel.
• The extreme heat causes the air to expand explosively, creating a shock wave that propagates outward as a sound wave.
• Thunder can range from a sharp crack to a low rumble.
• Sound is much slower than light.
• Seeing lightning before hearing thunder occurs due to the difference in speed of sound and light.
• The time interval between lightning and thunder can be used to estimate the distance to the lightning strike.
• Every 3 seconds between the flash and the sound approximates 1 kilometer (or every 5 seconds to 1 mile).
• Thunderstorms include:
  • Single-cell thunderstorms.
  • Multicell thunderstorms.
  • Supercell thunderstorms.
• Thunderstorms are most common in warm, humid regions where there is ample moisture and instability in the atmosphere.
• Thunderstorms typically occur during the afternoon and evening.
• Meteorology helps scientists understand and predict thunderstorms and their associated hazards.