April 14, 2018, IceBridge mission scientist John Sonntag spotted something he had never seen before. Sonntag snapped this photograph from the window of the P-3 research plane while flying over the eastern Beaufort Sea. At the time, the aircraft’s location was 69.71° North and 138.22° West, about 50 miles northwest of Canada’s Mackenzie River Delta. “We saw these sorta-circular features only for a few minutes today,” Sonntag wrote from the field. “I don’t recall seeing this sort of thing elsewhere.” The features are more of a curiosity than anything else. The main purpose of the flight that day was to...