Chuck's Commentary: As Cameron states, he gained another 400 meters (1300 feet) in elevation. He also traveled over 25 kilometers (15 miles) on the glacier. He is at the southern edge of Grimsvotn. Grimsvotn is a roughly 8 kilometer (5-mile)-wide steam cauldron caused by a volcano about 460 meters (1500 feet) below the icecap surface: the volcano is active, and it melts the ice, weakening it to create a steaming bowl. A few kilometers south of Grimsvotn is Haabunga. Haabunga is a roughly 5 kilometer (3 mile)-wide ice dome, also caused by volcanic activity. Cameron must thread a roughly 1.6 kilometer (1-mile)-wide gap of moderate terrain between Grimsvotn and Haabunga in order to make it to the inland ice.