Helio C. Vital in Rio de Janeiro, Brazil submitted these wonderful photos of intense sunsets this weekend caused by the dramatic eruption of Calbuco volcano in Chile on April 22. He wrote:
This was an awesome display of unusual colors in Rio`s sunset skies produced by aerosols from Chile`s Calbuco volcano passing high above the city at the top of the troposphere (10-12 km height). Wonderful pink, pastel, orange and red colors could be seen adorning most of the western sky. Sometimes the illuminated plumes of aerosols reached as far to the northeast as Venus. Residual pink color lasted until an hour after sunset as captured by my camera. In decreasing order of concentration, particulate size and heights, based on what I observed, I would relate the following colors: red, orange, pastel and pink (in that order). Pink, associated to the tiniest and highest aerosols is quite unusual and it was the last color to become visible to the naked eye. Most of the time, the sky remained orange, although the camera was able to capture all colors most of the time.
What a fantastic display of Nature! Venus, Jupiter and the moon added to the show.
Les Cowley at the website Atmospheric Optics explains more about seeing colors from volcanic aerosols:
Volcanic eruptions can inject millions of tons of dust and gaseous sulfur dioxide into the stratosphere. The finer dust particles remain aloft for years and spread around the world while the sulphur dioxide evolves to an aerosol of sulfur acids that add to the particulates.
The dust and aerosol produce vivid sunset and twilight effects like the intense yellow-red horizon and purple-pink glows of the photograph. The purple glow is probably a combination of red-orange light transmitted through the lower atmosphere and scattered blue light from still sunlit stratospheric dust.
Dramatic sunset colors from a volcano in one part of the world can persist for many months and be seen across the globe. When Mount Pinatubo erupted in the Philippines in 1991, its afterglows persisted to varying degrees for about 18 months after the initial explosion, according to Stephen F. Corfidi at NOAA/NWS Storm Prediction Center.
Bottom line: Watch a sunset! Maybe you’ll see some beautiful colors, caused by the eruption of Calbuco volcano in Chile.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.