4. The Impact of Altitude on Lightning Color
The apparent colour of lightning can be much changed by its altitude. Higher altitudes, usually exceeding 20,000 feet (6,100 meters), are common sites for blue lightning. The air is less dense at these altitudes, and less particles exist to disperse the light. This lets the blue wavelengths move more unhindered towards the observer’s eye.
Lighting strikes more air particles and moisture as it falls to lesser heights. By scattering and absorbing the blue light, these components can produce lightning that appears more white or yellow by the time it strikes the ground or is seen from a distance. Blue lightning is thus more often observed in high-altitude events like sprites and jets or in the top sections of thunderstorms.