külmakerge, pingo
igikeltsa alal pinnases leiduva vee külmumisest ja pinnase kerkimisest tingitud ajutine positiivne jääst tuumaga pinnavorm. Mineraalpinnases kujunevaid vorme nimetatakse pingodeks ja turbapinnases kujunevaid tavaliselt eelmistest väiksemaid vorme palsadeks., hummock on the land surface that occurs due to buried ice lenses growth in permafrost area and which collapse after 5-7 yrs. Pingos formed in mineral soil are usually larger compared to palsas in peat.