When water turns into ice in soil, it becomes frozen ground. Permafrost is ground that has been below 0 °C (32 °F) for at least two years. It consists of soil, gravel, and sand, usually bound together by ice. Learn more: bit.ly/3A0TKmO National Snow and Ice Data Center Mission Antarctica by @MissionAntarctica A @grttme project - Other backups: @Hallotme