Wildfires across the state of California have scorched nearly 1 million acres of land sending smoke billowing into the atmosphere. As the smoke rises it starts to move with the upper level pattern. In this week’s case that pattern is what links Iowa to California. More than 30-thousand feet off the surface of the earth, the wind is moving over a ridge, sending smoke particles from north central California through Idaho, Montana, the Dakotas, and eventually straight to Iowa. Now you cannot smell the smoke since it is so high in the sky, but it still creates the haziness we see during the day and the vibrant colors we experience at sunrise and sunset.
The colors we see have to do with how the light scatters.
Sunlight is made of all colors in the visible light spectrum, these are the colors we associate with a rainbow. Blue light scatters best, as it has a much shorter wavelength than red, which is why we see the sky as blue. But at sunrise and sunset the low angle of the sun allows for red and orange light to pass through the atmosphere as well. The light rays hit small molecules in the atmosphere and bounce off in all directions. However, smoke particles are much larger than gas molecules like oxygen and are able to scatter the longer wavelengths of red light, which is why we see a bright red sun during the early morning and late evening.