Dillon asks: "Todd, why does the sky turn green right before a tornado?"
Accounts of thunderstorms that appear green are rare, although historic records of them go back more than a century.
The weather oddity has even earned a place on reality TV. "Storm Chasers" on Discovery Channel featured an entire episode dedicated to the green skies often seen before hail storms and tornadoes.
Shy why does it happen? No one really knows, but there are two leading beliefs.
Theory #1 suggests storm clouds act as a dark backdrop, which makes sunlight scattered by air molecules appear blue.
Combining that with colors of a sunset can give clouds a greenish appearance.
However, the most popular theory is that the color comes from the thunderstorms themselves.
Storms have a lot of water, often in the form of hail, and the water or ice naturally scatter green light during the strong updrafts that occur in severe storms.
So those are two possible answers to your question.
The sky does occasionally appear green before severe weather, so if storms are moving in and the clouds have a greenish tint, take cover immediately.