Skeiðarársandur is a sandur, which is geologically speaking is a desert plain formed by the melting of ice caps, and this is quite simply the biggest one in the world, extending as far as the eye can see.
Literally, the “sandur of the Skeiðará River”, the Skeiðarársandur is the area to the south of the huge Vatnajokull ice sheet, a vast meltwater plain that collects all the glacial waters and rainwater flowing from the glacier.
The remains of the bridge destroyed by a Jökulhlaup in 1996 - Isabelle O'hara @dreamstrime
Bordered by Skaftafell Park on one side and the Atlantic Ocean on the other, Skeiðarársandur extends over 1,300 km², it's surface nearly 30 km wide by 56 km long, making it the largest sandur in the world. This immense desert consists of sand and gravel residues scraped by the ice from the Vatnajökull ice cap.
Skeiðarárjökull is one of the glacier tongues of the Vatnajökull cap, and the meltwater creates the Skeiðará river, and others such as the Blautakvísl or the Gígjukvísl that you can see meandering through the dark dunes of the Skeiðarársandur.
It's record breaking size, being the largest Sandur in the world, can be explained by a few factors. It is located at the foot of an ice cap, but this ice cap has the particularity of covering numerous volcanoes. And when a subglacial volcano erupts, known locally as a Jökulhlaup, this can cause a chain reaction, a glacial outburst flood. This violent and very rapid melting of the ice that generates a torrent that mixes with the rivers and carries away everything in its path.
This happened here several times, most recently in 1996, during the eruption of the Grímsvötn volcano. To give you an idea of the flood's power, normally the Skeiðará river has a flow of 200 to 400 m³. When this eruption hit, the water flow jumped to 50,000 m³ per second! Nearly 12.8 million m³ of sediments were deposited during the eruption and washed out across the Sandur. The Jökulhlaup took everything in its path and completely destroyed Road number 1 between Skaftafell Park and the ocean. In fact, a piece of a metal bridge facing south from Skaftafell Park (see photo above) stands testament to the awesome power of the event.
These Jökulhlaups are the worst nightmare for many Icelanders as these are the most frequently occurring volcanic hazard, and they are devastating. There are countless scars especially in the south of the country from the damage of these floods after the eruptions of Grímsvötn, the huge Öræfajökull, or Katla further west.
Skeiðarársandur seen from Skaftafell
Skeiðarársandur can be seen from far away, being so incredibly huge, so there are several way to "visit" it. You can tour it yourself stopping in several small car parks along its northern edge with information points for short walks in this large desert. But the best way to experience the vastness and beauty of the Skeidararsandur is probably by visiting a viewpoint in Skaftafell Park.
Indeed, in the park from the orientation table in Sjonarsker you have a breathtaking view of the sandur and the nearby Sel farm (photo), or even Sjonarnipa.
The soil of Skeiðarársandur is gritty and even rocky as you get near the glacier, but closer to the sea it turns into sand and clay. This is where it is very common to be able to observe “big skuas”, these large, slightly aggressive birds found in southern Iceland.
Just before turning off at Skaftafell, stop near the famous memorial to the bridge destroyed in 1996, bent out of shape like a paperclip.
If you really want to appreciate the scale of this natural feature, you can book an excursion via tourist plane. The tour lasts about 45 minutes and covers Skaftafell and its glacial tongues as well as the vast desolate expanse of Skeiðarársandur.
Skeiðarársandur is very easy to reach as it is located right along the ring road, number 1. The 1996 Skeiðarársandur Memorial is only 4 km from Skaftafell Park and there are plenty of parking lots along the Great Desert.
Once you cross the huge metal bridge named Skeiðarárbrú, which crosses the Morsá River, you are officially in the sandur region.