'Nuclear' cloud over Saint Petersburg
Thoughts of a disaster passed through the minds of alarmed citizens, but the Emergencies Ministry gave reassurances that none had been reported.
Meteorologists say the strange-shaped cloud may have formed as a result of rare atmospheric conditions in the area, which had been experiencing alternating sun and rain showers.
Doubt has been cast on the explanation by skeptics who pointed out that clouds are formed high in the sky, while the mushroom cloud appeared to be rising from the ground.
Some St. Petersburg residents say photos of the cloud suggest it must have been produced artificially.
“We had fog yesterday, but it's a morning event. Of course a mushroom-shaped cloud could appear, because there were many rain clouds. But it happens at great altitude. It's unlikely to happen near the ground,” meteorologist Aleksandr Kolesov said.
However, the cloud in question only gives the appearance of touching the ground but is actually as high as it is supposed to be, he added.
“The photo was taken from afar, and that's why it looks like that,” he said.
Atmospheric phenomena can sometimes be very peculiar. In December 2009, for instance, a Russian missile test resulted in a spiral cloud appearing in Norway's sky.