2007 Siberian orange snow

The Siberian orange snow of 2007 was an anomalous phenomenon that occurred in early February 2007. Beginning on 31 January 2007, an orange-tinted snow fell across an area of 1,500 square kilometres (580 sq mi) in Omsk Oblast, Siberian Federal District, Russia, approximately 2,300 km (1,400 mi) from Moscow, as well as into the neighboring Tomsk and Tyumen Oblasts. It was unclear what caused the orange snow. Speculation ranged from pollutants to a sandstorm in neighboring Kazakhstan.