What word or phrase does your mother always say?
Plural pingos or pingoes
A large mound or dome of ice covered with soil. Pingos are about 30 to 50 m (98 to 164 ft) high and up to 400 m (1,312 ft) in diameter and are found in Arctic regions. They are believed to form in basins (such as drained lake beds) as a result of the freezing and upward expansion of water held in subsurface soil, which initiates the doming, as well as by the rising and freezing of water trapped beneath or within the permafrost, as a result of hydrostatic pressure.