A huge, eery flash that appeared to shoot up as a beam of light into the night sky has spooked residents of a city in southern Russia.
The pulsing light that briefly bathed the city of Stavropol white and blue on Monday night was caught by a dash cam mounted in a car, the video of which has spread across social media.
The dazzling burst of light seemed to knock out some streetlamps in the city, as seen in another webcam video.
The event has become all the stranger because nobody has so far been able to explain what it was. Local scientists today ruled out that natural phenomena could have caused it.
“This flash cannot have been natural,” Svetlana Solovyova, chief analyst at the Stavropol Meteorological center told local media.
"It wasn't a meteorological event. There wasn't a storm," said Natalya Klimenko, an analyst at the center, told ABC News. "More likely it is something made by a human being.”
Theories quickly rose to fill the gap: the light was part of huge military exercises, which are currently underway across Russia involving 80,000 troops; others believed the inexplicable lights were proof of aliens, pointing to the fact that similar flashes have appeared in at least four other cities.
“It’s a kind of photo-flash,” Sergei Pakhamov, a UFO-ologist, told local state TV. “They were photographing the city.”
A popular kitsch Russian singer in Stavropol giving a concert Monday night was also blamed.
One likely explanation seemed to be the coincidence of the lights with another rare phenomenon: the aurora borealis “Northern Lights” appeared over Moscow on Monday, coming far further south than normal.
The lights, which are normally confined to the Arctic circle, were visible because of a vast magnetic storm which charged particles at a much lower altitude. But scientists have now also ruled out that the blue flashes over Stavropol could be connected.
This is far from the first time bizarre lights and explosions have appeared over Russia, where inexplicable phenomena in the sky have become remarkably frequent occurrences. In 2014, a huge blast turned the sky orange over Siberia; in 2013 a massive meteorite exploded over Chelyabinsk, blowing out almost every window in the city.
Most of these incidents were also caught on dash-board mounted cameras, which have become ubiquitous in Russia, where they are used to ward-off corrupt traffic cops but have also captured the bizarre from cow-crashes to punch-ups.
This time-however a meteorite has been ruled out by scientists, who say it would have been detected by radar.
The strange celestial phenomena -- combined with the many military drills and the confrontation with the West over Ukraine, the burning of one of Moscow’s major monasteries and the unexplained disappearance of Vladimir Putin for 10 days last week -- have all contributed to a peculiar end of days sensation for many Russians. The solar-eclipse scheduled to occur Friday for some caps it.
But the most likely cause of Monday's flashes may be more banal- though still peculiar to Russia. Yuri Varakin, a local meteorologist also at the Stavropol Center, told ABC News that he believed the lights were most likely caused by a special high-powered projector lamp used by airports to measure the height of clouds. He said, the light is turned on in a burst when there is heavy cloud, which causes the widespread illumination. He explained that such devices are no longer found in Europe or the US, where lasers are now used.
An official at Stavropol airport confirmed to ABC News that the device had indeed been used on the night of the flash because there were thick snow-clouds.
But this explanation does not not explain why the flash appeared to knock-out some streetlights. Scientists at the meteorological center say they are continuing to investigate.