Skeiðarársandur, the largest sandur in the world, covers a 1300-sq-km area and was formed by the mighty Skeiðarárjökull. Since the Settlement Era, Skeiðarársandur has swallowed a considerable amount of farmland and it continues to grow. The area was relatively well populated (for Iceland, anyway), but in 1362 the volcano beneath Öræfajökull (then known as Knappafellsjökull) erupted and the subsequent jökulhlaup (flooding caused by volcanic eruption beneath ice) laid waste the entire district. After the 1362 eruption the district became known as Öræfi (Wasteland).
The section of Ring Road that passes across Skeiðarársandur was the last bit of the national highway to be constructed – as recently as 1974 (until then, Höfnites had to drive to Reykjavík via Akureyri). Long gravel dykes have been strategically positioned to channel floodwaters away from this highly susceptible artery. They did little good, however, when in late 1996 three Ring Road bridges were washed away like matchsticks by the massive jökulhlaup released by the Grímsvötn (or Gjálp) eruption. There’s a memorial of twisted bridge girders and an information board along the Ring Road just west of Skaftafell.