HOUSTON – If you've noticed recently that our sunrises and sunsets have had a purple tint to them, it's not just you, it's Russia.
Raikoke, an active volcano on the Kuril Islands, erupted in June of this year, spewing volcanic ash into the atmosphere. In fact, the ash cloud rose into a particular layer of the atmosphere called the stratosphere.
It's about 7.5 miles above the surface where stronger jet stream winds can transport the ash and dust particulates in the cloud thousands of miles away. In this case, these ash particles have made their way across the ocean into the skies of North America.
The particles change the way the sunlight is scattered, being most pronounced during the hours around sunrise and sunset. These particles cast a purplish tone to the sky as it is reflected and absorbed in the ozone layer. The last time we saw a similar phenomenon was in 1991 after the eruption of the Mt. Pinatubo, in the Philippines.
While there is no threat to the added ash particulates in the sky, it is a good reminder that even a small scale eruption can have major consequences. Large scale eruptions can cause not just changes in the sky color but actually have global effects.
In 1815, a large eruption from Mt. Tambora in Indonesia sent a plume so large into the atmosphere that the following year was called "The Year Without Summer" because a large amount of sulfur dioxide and other large particles shaded the Earth, decreasing the amount of solar light that reach the surface, affecting everything from seasonal temperatures and crops failing to grow.
So if you see a little more purple in the sky tonight, give a "spasibo," which is Russian for "thank you" for the view.