Noctilucent clouds — the world’s rarest clouds — appeared over the San Francisco Bay area during the early hours of Friday morning, just a few days after yet another SpaceX rocket launch.
Rain Hayes, a local photographer, saw the clouds sailing over Lake Merritt in Oakland two days ago at around 6.30 a.m. before sharing images of the rare sighting later on social media.
‘Strange bright cloud over Lake Meritt during the tail end of astronomical twilight this morning,’ she wrote, while also notifying the National Weather Service’s regional office.
‘Great shot of what appears to be a noctilucent cloud over the SF Bay Area this morning!’ UCLA climate scientist Daniel Swain said in response to Hayes’ photo.
San Francisco Bay Area resident Rain Hayes caught the moment rare noctilucent clouds go over Lake Merritt in Oakland on Friday, December 16
Some scientists believe the increase in noctilucent clouds could be due to excessive water vapor in the atmosphere from rocket launches. On Friday, a Space X launch was organized for the departure of a Falcon 9 rocket into space
UCLA climate scientist Daniel Swain called noctilucent clouds ‘very rare’ and said they formed in the mosephere about 50 miles up into the sky
‘Such clouds are very rare at this latitude and also in winter, and are the Earth’s highest and driest clouds, forming in the mesosphere about 50 miles (!) up. Wow!’
The National Weather Service eventually confirmed that noctilucent clouds had been in the Bay Area prior to sunrise, and that their passing was somewhat unusual.
Noctilucent clouds are usually only found on Earth’s extremities: the North and South Poles. In the US, they typically appear on the West Coast and only in the Pacific Northwest.
Also called polar mesospheric clouds, noctilucent clouds form between 47-53 miles above Earth’s surface (76-85 km), according to NASA.
Here, atmospheric circulation pushes air upwards, which then expands and cools.
Water then vapor becomes trapped in the clouds, freezes into ice crystals, and forms meteoric dust.
Noctilucent clouds or night shining clouds typically form in late spring and early summer when the lower atmosphere becomes warmer. Pictured: Noctilucent clouds in Sweden in 2020
Noctilucent ‘night shining’ clouds over Lancashire in the United Kingdom in 2019. Sightings of this specific type of clouds have increased over the last decade, according to scientists
The clouds are also seeded by debris from disintegrating meteors, giving them a ‘shocking’ blue hue when they reflect sunlight. They typically form in late spring and early summer when the lower atmosphere becomes warmer.
Noctilucent clouds can even be seen from space, as astronauts at the International Space Station have previously shared pictures of the phenomenon.
In July, DailyMail.com reported sightings in certain parts of the US, Canada, and Europe over a single weekend.
There is some belief that climate change is also contributing to their development and even to them being seen at latitudes never seen before.
For example, in 2019, they were seen as far south as Joshua Tree, California, which suggests that with more greenhouse gases in the atmosphere, there is more water vapor available for the glowing clouds to form.
Cora Randall, a professor at the University of Colorado Boulder, told The Washington Post that the increase in clouds could be due to excessive water vapor in the atmosphere from rocket launches.
Noctilucent clouds can even be seen from space but usually only form in the North or South Pole
A SpaceX Falcon 9 rocket lifts off from Cape Canaveral Space Force Station in Florida on Friday, December. On board were two O3B mPOWER communications satellites for SES Luxembourg
On Friday, a Space X Falcon 9 rocket launched the SWOT water-watching satellite for NASA from California’s Vandenberg Space Force Base.
On Saturday, Space X launched another Falcon 9 rocket for an unprecedented 15th time in a calendar year.
Another study suggests that the appearance of noctilucent clouds fluctuates from year to year and even from decade to decade, but that overall, they have become ‘significantly’ more visible.
Meanwhile, noctilucent clouds were first described in the mid-19th century after the eruption of Krakatau.
Volcanic ash spread through the atmosphere, making for vivid sunsets around the world and provoking the first known observations of NLCs.
At first, people thought they were a side effect of the volcano, but long after Krakatau’s ash settled, the wispy, glowing clouds remained.