As one of Eyjafjallajokull Glacier´s Outlets, Gigjokull was close to the head of the Eyjafjallajokull volcanic eruption in 2010. Powerful glacial bursts emerged from Gigjokull during the eruption, flooding the plains below.
Gigjokull empties out of the summit crater area at 1600 meters (5249 feet), flows across the ice cap to 1500 meters (4921 feet) and then descends in an icefall down 200 meters (656 ft). Water flowing from Gigjokull enters the Markarfljot river.
Two glacier tongues fall steeply down to the foot of the northern slopes of Eyjafjallajokull. The Gigjokull and The Steinsholtsjokull. Both end in lagoons, where it usually is possible to see some floating ice. In 1967 a part of a precipice called Innstihaus, about 15 million cubic metres, broke of and collapsed on top of the glacier and into the lagoon from about 900 feet above. This catastrophe caused a tremendous flood wave, carrying with it gigantic rocks and boulders all the way down to the main river, Markarfljot, which peaked at 21.000 cubic metres per second.
Two aircraft have crashed on the icecap. In 1952 an American rescue plane, with five on board, went down and only one body was found on location. The other four obviously had escaped and walked away, not to be found during the next few years. Twelve years later, another body was found and a wedding ring of another. The glacier tongue delivered the remaining three bodies in the summer of 1966. Scrap and pieces from the plane have been appearing gradually in and by the sides of the glacier. In 1975, an American couple crashed and lost their lives.