2007 Siberian orange snow

The 2007 Siberian orange snow is a heavy sandstorm in neighbouring Kazakhstan.

Description

This orange snow was malodorous, oily to the touch, and reported to contain four times the normal level of iron. Though mostly orange, some of the snow was red or yellow. It affected an area with about 27,000 residents. It was originally speculated that it was caused by industrial pollution, a rocket launch or even a nuclear accident. It was later determined that the snow was non-toxic; however, people in the region were advised not to use the snow or allow animals to feed upon it. Coloured snow is uncommon in Russia but not unheard of, as there have been many cases of black, blue, green and red snowfall.

Cause

This orange snow was most likely caused by a heavy sandstorm in neighbouring Kazakhstan. Tests on the snow revealed numerous sand and clay dust particles, which were blown into Russia in the upper stratosphere. The speculation that the colouration was caused by a rocket launch from Baikonur in Kazakhstan was later dismissed, as the last launch before the event took place on 18 January.

Russia's environmental watchdog originally claimed that the coloured snowfall was caused by industrial pollution. It stated that the snow contained four times the normal quantities of acids, nitrates, and iron. However, it would be nearly impossible to pinpoint a culprit if pollution were the cause, as there are various industries nearby, such as the city of Omsk, which is a centre of the oil industry in Russia.