The landscape is very similar to some of the Alps, but it has been formed over thousands of years by different influences of fire (volcanic eruptions of Öræfajökull) and water (the glaciers Skeiðarájökull and Skaftafellsjökull), the rivers Skeiðará, Morsá und Skaftafellsá. Volcanic eruptions under the ice-cap can give rise to jökulhlaups (glacial floods) which swell the Skeiðará river massively. The sandy wasteland between the glacier and the sea caused by jökulhlaups is called Skeiðarársandur, and is a typical outwash plain known locally as a sandur. The last large jökulhlaup occurred in 1996.