Why Are Clouds White?

Why Are Clouds White?
SEATTLE - First of all, you have to remember that white light is made up of the 7 colors of the rainbow -- red, orange yellow green, blue, indigo, and violet (Just remember ROY G. BIV).

In the meantime, clouds are collections of tiny water droplets and ice crystals. Each of those droplets and crystals will reflect each color of light equally, combining to make them appear white.

As for what causes our familiar gray clouds around the Northwest? That's caused by higher clouds casting their shadow on lower-based clouds, or that the clouds are so dense that their top parts absorb most of the sunlight, casting their own shadow along their base, making them dark on the bottom (the part you see.)