We've seen plenty of strong thunderstorms this month across southern Colorado. A News Five viewer recently reached out to ask us why the sky sometimes turns green ahead of strong thunderstorms and what it means.
Here's what we're talking about: a dramatic, almost dreamlike green color to the clouds as if taken from a movie. Sometimes, the clouds end up taking on a more bluish color instead. It all depends on the time of the day. But whether the sky looks blue, green, or teal, this color signals an intense storm and time to immediately go inside.
Let's zoom in on a thunderstorm. Thunderstorms contain a lot of water. Strong thunderstorms will also contain hail. Raindrops and hail do some cool things with the light from the sun. They tend to absorb the redder colors and leave the blue colors to bounce around the cloud. For a regular thunderstorm, this leads to a bluish-grey color in the cloud. But ice is particularly good at scattering blue light, so when a storm contains a lot of hail or ice crystals too, it makes the cloud take on a dramatic blue to teal color.
Now you may remember from school that blue and yellow together make the color green. The same applies to a green sky from a thunderstorm.
Late in the day, the sun is low in the sky, and the color is yellow to orange.
So when the yellow light from the late-day sun hits the blue light scattered by a thunderstorm that contains a lot of ice, you get green.
It takes an incredibly high amount of water and ice to create these colors. So a green sky is a visual signal that the storm approaching is incredibly intense. Large hail is almost certain in these storms. You may have even heard that a green sky can be a signal of an approaching tornado. This is partly true. A green sky can happen only with very organized, intense, and most often rotating thunderstorms. In short, if the storm is powerful enough to turn the sky green, it's often strong enough to produce a tornado.
So if you see the sky turn green, yes, it's impressive, but seek shelter in a substantial building
____
Have a question or story idea you would like the First Alert 5 Weather team to consider? Email: weather@koaa.com
Watch KOAA News5 on your time, anytime with our free streaming app available for your Roku, FireTV, AppleTV and Android TV. Just search KOAA News5, download and start watching.
