Reindeer herders in Russia's Far North have discovered yet another mysterious giant hole about 30 kilometers away from a similar one found days earlier.
Located in the permafrost of the subarctic Siberian region of Yamal, which means "end of the earth" in the local Nenets language, both craters appear to have been formed in recent years and have icy lakes at their bases.
Scientists who examined the first hole theorized that it could have been created when a mixture of water, salt and gas exploded underground, the Siberian Times news site reported.
The area, which has one of Russia's richest deposits of natural gas, was covered by sea about 10,000 years ago, and vast salt deposits were left behind.
"Global warming, causing an alarming melt in the ice under the soil, released gas causing an effect like the popping of a Champagne cork," the news report said, citing an expert at the Subarctic Scientific Research Center.
The first hole is estimated to be about 50 meters wide and 70 meters deep, with water from melting permafrost cascading down its sides into the icy deposit below.
The second hole is "exactly" like the first one, but "much smaller," local lawmaker Mikhail Lapsui told the Interfax-Ural news agency. "Inside the crater itself, snow can be seen."