Folks in western Arizona were caught breathless by these ethereal clouds shimmering over Quartzsite, earlier this week. Some thought the formation was residue left over from a rocket launch from nearby Vandenberg Air Force Base in California, but there were no rocket launches that night.
The only explanation is some sort of cloud formation.
At first glance, it looks a lot like cloud iridescence. Cloud iridescence is a common meteorological phenomenon that occurs when sunlight or moonlight passes through the liquid water droplets in the cloud producing a pastel rainbow appearance, very similar to the process of how rainbows form. Often times, the appearance of cloud iridescence is compared to oil films in water.
Cloud iridescence is one theory.
What caught my eye, and the eyes of several other meteorologists, was the idea that these could actually be noctilucent clouds instead. Noctilucent clouds are rare already, and that they were seen in a southern latitude makes this an exceptional capture!
Latin for “night shining,” noctilucent clouds are made of ice crystals that are located very high in the atmosphere, that are only visible in deep twilight.
Noctilucent clouds are the highest clouds in Earth’s atmosphere, located in the Mesosphere ~50 miles above the surface. The colors occur when sunlight passes through the ice crystals, similar to how sun dogs or halos form. However, the colors associated with noctilucent clouds are typically more faint than sun dogs due to the very small and thin nature to the moisture-starved ice crystals located that high in the atmosphere. In fact, the mesosphere contains very little moisture, approximately one hundred millionth that of air from the Sahara desert.
According to EarthSky, there’s a very narrow window to see them:
Noctilucent clouds are primarily visible when the sun is just below the horizon, say, from about 90 minutes to about two hours after sunset or before sunrise. At such times, when the sun is below the ground horizon but visible from the high altitude of noctilucent clouds, sunlight illuminates these clouds, causing them to glow in the dark night sky.
While they are most common between 50 and 70 degrees north latitude, they have been seen as far south as Denver and Orlando. They are most commonly seen during late spring and summer, and historical observations reveal they have been recorded more frequently across the northern hemisphere than the southern hemisphere.
Noctilucent clouds are not fully understood by scientists, with NASA and others doing research to get a better grasp on how these form.
Everything from rocket launches, to reentry of space vehicles, to explosive volcanic eruptions have been postulated as possible contributors to the formation of these elegant, practically out-of-this-world meteorological phenomenon.
The jury is still out whether this cloud formation captured by David Laucks was in fact the exceptionally rare noctilucent clouds, or simply the more common cloud iridescence.
Weather is awesome. #cwgpicoftheweek