Pictures of the bizarre sight of the emerald snow appeared on social media.
Scientists rush to site of latest tundra eruption - which formed a crater 50 metres deep - amid fears for homes and key industrial sites.
Prime minister raises the issue on sidelines of the Asia-Europe Meeting (ASEM) in Ulaanbaatar.
A renaissance of one of Siberia's first outposts as the Far North becomes the new economic frontier.
Threat to Salekhard and Anadyr could come even sooner - by the mid-2020s - as thaw of frozen ground is forecast to have 'devastating' impact.
Massive Siberian source of diamonds formed by an asteroid 35 million years ago can 'overturn entire world gem market'.
Gas bubbles from waters filling crater hole on Yamal peninsula two months after volcanic-style explosion in thawing permafrost.