Stock Photo: Hikers traverse the ash-blackened Vatnajokull Glacier. Black ash from volcanic eruptions darkens the ice at the Vatnajokull Glacier. Vatnajokull is the largest glacier in Iceland. It is located in the south-east of the island, covering more than 8% of the country. Vatnajokull is the largest ice cap in Europe. The average thickness of the ice is 400 meters, with a maximum thickness of 1,000 meters.