A new crater has been blasted into the Siberian tundra by the violent release of a massive pocket of methane gas that had accumulated beneath the surface of the earth. While the massive 165-foot hole is not the first to have been found to have been formed in this manner, it is one of the first to have a witness to the explosion that created it.

On June 28, reindeer herder Yakov Vengo was camped out on Siberia’s Yamal peninsula, 35 to 40 kilometers north-west of the village of Seyakha, when a nearby pingo mound — a type of hill found in the Arctic — exploded. The explosion was heard in nearby Seyakha, and also registered on local seismographs. The resulting crater is now part of the riverbed that the pingo that caused it was situated near.

"There were fire, smoke and huge chunks of soil ‘flying out’ of the epicentre," according to Vengo’s friend and fellow herder, Mikhail Okotetto, recounting what Vengo told him in an interview with Vesti-Yamal television. "The hill has vanished."

A second crater, referred to as "funnels" by the researchers studying them, formed earlier, sometime over the winter. The explosion that formed it apparently also had witnesses: "The Nenets native people told us they saw fire in winter 2017, but it might mean January to March or April. In other words, it exploded when snow was still lying," explains Dr. Alexandr Sokolov, deputy head of the Arctic Research station of the Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences.

These two new craters are now part of a group of ten known funnels formed in this fashion, along with dozens of smaller ones spotted from the air. Pingos are traditionally formed when permafrost begins to swell in response to hydrostatic pressure from a water source. As the permafrost melts due to global warming, trapped methane is released, but can build up under the still-frozen cores of some pingos — and can explode violently and unexpectedly. There are fears that future explosions could catastrophically damage infrastructure from Yamal LNG’s natural gas extraction project on the nearby Yuzhno-Tambeyskoye gas field.