A red sky during storms or wildfires is caused by an enhanced version of Rayleigh scattering combined with particular atmospheric conditions. This occurs when:
- Smoke particles or storm clouds fill the air
- These particles are larger than normal atmospheric molecules
- They scatter light differently than clean air
During these events, the larger particles allow more red light to pass through while scattering other colors. The effect is intensified by:
- High concentrations of smoke or dust
- Moisture in the air
- The angle of the sun
This phenomenon can be particularly striking during wildfires because smoke particles are exactly the right size to scatter red wavelengths while blocking other colors, creating an eerie, apocalyptic appearance.