Ground-based measuring devices and aircraft radar operated in the far northeast of Greenland show how much ice the 79 N-Glacier is losing. According to recent measurements, the thickness of the glacier has decreased by more than 160 meters since 1998. Warm ocean water flowing under the glacier tongue is melting the ice from below. High air temperatures cause lakes to form on the surface, whose water flows through huge channels in the ice into the ocean. One channel reached a height of 500 meters, while the ice above was only 190 meters thick.