Sydney Morning Herald - Mar. 01 (Special Report) - The Siberian crater wasn't alone. There were two more, ratcheting up the tension in a drama that hit its climax as a probable explanation surfaced. Climate change had thawed the permafrost, which had caused methane trapped inside the icy ground to explode. "Gas pressure increased until it was high enough to push away the overlaying layers in a powerful injection, forming the crater," one German scientist said at the time.