I see Kyle's Russian thermokarst example and raise him thermokarst plus volcanoes. According to the Smithsonian's Global Volcanism Program: "The Ingakslugwat Hills consist of at least 32 small cinder cones and 8 larger craters covering an area of more than 500 sq km in the Yukon-Kuskokwin delta area of SW Alaska. Numerous small spatter cones and cinder cones of the Ingakslugwat Hills range from 8 to 190 m in height; many are concentrated in the NW side of the volcanic field." 61.43° -164.47° Flash Earth image: http://www.flashearth.com/?lat=61.526696&lon=-164.750237&z=10.5&r=0&src=msa