Figure 17.4
Pingo and patterned ground. (A) Pingos can reach 50 m (160 ft) in height and range from the size of a car to the size of a large hill, like the one shown here. This pingo is in the McKenzie River delta in Canada. (B) This patterned ground is in the Farnell Valley, Antarctica.(A. Jason Pineau/All Canada Photos/Getty Images; B. © Maria Stenzel/National Geographic/Getty Images)